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DUKE UNIVERSITY PUBLICATIONS 


A LABORATORY MANUAL 
OF GENERAL BOTANY 





A LABORATORY MANUAL 
OF GENERAL BOTANY 


BY 


HUGO LEANDER BLOMQUIST 


— 
Professor of Botany in Duke University 
AND 


NUMA FRANCIS WILKERSON 


Instructor in Botany in Duke University 


(REVISED EDITION) 


DUKE UNIVERSITY PRESS 


DURHAM, NORTH CAROLINA 


1926 


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PREFACE Biology Dept. Library 


It is a fact, quite generally recognized, that no manual of 
botany, regardless of its merits, has ever been written which suits 
every instructor or is applicable to every method of teaching or 
organization of the course or to every institution or locality. 
The principal reason for this lies in the nature of the laboratory 
material. While there is a more or less conventional method of 
presenting the subject in the lectures, there is no science in which 
the laboratory material may be varied so much as it may in the 
study of plant structures and plant life. It is fortunate that this 
is so, since fresh material should be used as much as possible, and 
considerable time should be devoted to field work. 

Since no manual has so far been found entirely suitable for 
the course in general botany as it is given at Duke University, 
this one was prepared. Its purpose is to aid the instructors and 
to guide the students in the laboratory and in the field. The 
authors have taught this course for six consecutive years in the 
same institution and have used the material and methods here 
published both in multigraph sheets and in printed loose-leaf 
notebook form. During that time the authors have made a 
special study of the organization, methods, and materials em- 
ployed in the laboratory work, and many revisions and changes 
have been made. 

The selection of material and its arrangement are origi- 
nal in so far as a laboratory manual may be said to be original, 
although helpful suggestions have been obtained from such 
manuals as Transeau and Sampson’s, Densmore’s, and Hol- 
man’s. Several different textbooks have been used with this 
manual, and the experience has been that it may be used with 
equal success with any good modern text. 

The authors wish to express their appreciation to the editors 
and to Dr. Bert Cunningham for many helpful suggestions and 
to the Bausch & Lomb Optical Company for permission to use 
Figure 1 taken from their booklet, Use and Care of the Micro- 


scope. H. L. Buomeguist 


N. F. WiInKeErson 
Duke University, 
April 15, 1926. 


177174 








A LABORATORY MANUAL 
OF GENERAL BOTANY 


a 





PRELIMINARY INSTRUCTIONS 


LABORATORY STUDY 


In the biological sciences the laboratory method of study has 
proved itself to be the most successful method. The reason for 
this is that when one sees a thing with his own eyes he forms 
a definite image of it and consequently understands and retains 
it much better than if he simply reads about it. Huxley, one of 
the greatest teachers of biology that ever lived, once said, ‘*. 
all language is merely symbolical of the things of which it treats; 
the more complicated the things are, the more is the symbol, and 
the more its verbal definition requires to be supplemented by the 
information derived directly from the handling, and the seeing, 
and the touching of the things symbolized.’’ Another great 
teacher of biology, Louis Agassiz, gave expression to the same 
idea when he said, ‘‘Study Nature, not books.’’ These men did 
not mean, of course, that books should be entirely discarded from 
biology courses; their great emphasis upon laboratory study was 
due to the fact that they were living in an age when the labora- 
tory was an innovation in the institutions of learning. 

The laboratory method does not mean that the plants and 
animals should necessarily be studied indoors; the point is simply 
that the information is obtained first-hand by seeing and by 
studying, experimenting, drawing, describing, and interpreting 
what one sees. Indoor study has probably been over-done. In 
earlier times the laboratory of students of animals and plant 
life was mostly the out-of-doors, walled in by the horizon or the 
limit of vision and roofed by the dome of the blue sky. But of 
course their aim was different from that of students of today. 
They were primarily concerned with the mode of living, or 
natural history, and classification of the plants and animals, and 
the only necessary equipment was a magnifying glass. Because 
of the tremendous development of the subjects of morphology, or 
the study of structure, and physiology and the subdivisions of 
these subjects since the middle of the last century, it has become 
necessary to have an indoor laboratory as a place where the 
necessary equipment is housed and where it may be most effi- 


[3] 


ciently used. While much of the study must be done in this 
laboratory, it should be supplemented as much as possible by 
outdoor or field work. 

A student who has had no experience in laboratory study is 
more or less confused when he enters a laboratory for the first 
time. He seems utterly helpless and at loss as to what to do. 
A few remarks about what to do and how to act in the laboratory 
may therefore be helpful. One of the first things to do in the 
laboratory is to learn to observe. This is one of the most essen- 
tial things in all laboratory study; power of keen and critical 
observation is an important part of a good biological training. 
A second point is the cultivation of a proper mental attitude. 
Looking at an object and drawing it is of little value unless one 
does it with an inquiring mind. Ask yourself questions con- 
tinually. What am I trying to do? What am I looking at? 
How does this organism or this structure differ from those 
studied before? What are these structures for? What does it 
all mean? Study the things you are looking at as if you were 
the first person to see them. Remember, the organism or the 
structure you are looking at very probably never was seen by 
human eyes before. This mental attitude has brought forth 
many startling discoveries in the past and will no doubt do the 
same in the future. 

Be industrious; be persistent; strive for improvement in 
your work. Work independently. Make use of your time in the 
laboratory. It is an invaluable opportunity. Do not hurry, but 
be thorough. Be sociable, but not to an extent that it interferes 
with your own work or with that of another. 


THE USE OF THE MICROSCOPE 


The compound microscope is an instrument which deserves 
the highest admiration, wonder, and respect of everybody. For 
one thing, it has taken the labor of some of the best minds in 
several centuries to bring it to its present state of perfection. 
Again, the use of this instrument has led to many important dis- 
coveries vital in bringing to pass our present high state of civili- 
zation. It is useless to enumerate these discoveries here, because 
only an advanced student of biology and its history can fully 
appreciate them. 


[4] 


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Some of the first things to learn in the use of the microscope 
are, how it is made, upon what principles it is based, and the 
names of its different parts. The instructor will tell you these 
things, but a study of Figure 1, which is a diagramatie drawing 
with the different parts labeled, will help you to remember them. 

An important thing to be observed is the correct position of 
the microscope with reference to the student and of the student 
with reference to the microscope. The chair of the student 
should be high enough so that he can look into the microscope 
comfortably without breaking it at the joint. The advantages of 
the upright position of the microscope are that better light is 
secured and, if one is examining a drop of liquid, it will not run 
off the slide. Since students are of various sizes, an adjustable 
chair is necessary. The handle arm of the microscope should face 
the student. 

The second matter of importance is the location of the light. 
Looking in the microscope with your right eye, take hold of the 
mirror with the left hand, if the light is from the right, or with 
the right hand, if the light comes from the left. Face the mirror 
towards the hight at an angle of about forty-five degrees so that 
the light is reflected upward through the opening in the stage. 
The microscope has a coneave and a plane mirror. Students are 
sometimes confused as to which mirror to use, and this should, 
therefore, be cleared up at once. Use the concave mirror when 
the source of light is near, as when using artificial light, and 
when no condenser is used. For daylight it is better at all times 
to use the plane mirror. Always be sure that you have obtained 
the best hight possible. For high-power magnifications, suecess 
depends upon having good light. 

See to it that the ocular and objective lenses are clean and 
that the microscope is in perfect focus. Do not be satisfied until 
the object is perfectly clear and distinet. Clean lenses and per- 
fect focus will give this result. Always use the low power first; 
do not use the high power unless necessary. In searching for an 
object, always use the low power. If you can not find it with the 
low power, you surely can not find it with the high. In changing 
from low to high power, the object must be in the center of the 
field, otherwise you will have difficulty in finding it. While look- 


[6] 


ing in the microscope, never focus down very far, especially 
when using the coarse adjustment; because, if you do, you will 
sooner or later break the slide. 

Place the slide on the stage so that the object you wish to 
examine is as near the center of the opening of the stage as 
possible. Using the low power (the shorter objective), turn down 
the tube until the objective is about an eighth of an inch from the 
slide. Then, looking into the microscope, raise the tube with the 
coarse adjustment until something is seen. Now use the fine 
adjustment for getting a sharper focus by turning it up and 
down or to right and left, as the case may be, depending upon 
the make of the microscope. In using the high power (the longer 
objective), the objective must be lowered until it is so close to the 
slide that you can just barely slide a thin paper between. Then, 
looking into the microscope, proceed as with low power. Remem- 
ber, it is much more difficult to use the high power than the low. 
At the end of the period, straighten up the microscope, raise the 
tube slightly, and leave it in low power. Be very careful not to 
turn the tube down so far that the objective goes through the 
opening in the stage. This will break the diaphragm if it is not 
opened wide. 


INTERPRETATION OF MICROSCOPICAL IMAGES 


Most objects look flat in the microscope. Very few of them 
are. Train yourself to see in three dimensions. In order to get 
the proper perspective, the object must be studied at different 
levels. With the fine adjustment, focus on the upper, middle, 
and lower levels. For objects larger than the field of the micro- 
scope, the slide must be moved. This is rather difficult, since the 
movements are also magnified, and the object is reversed. If you 
wish to move the image to the right, move the slide to the left, 
and vice versa. 

SLIDES AND COVER GLASSES 


Good laboratory work includes a minimum amount of break- 
age of slides and coverglasses. Be especially careful with pre- 
pared slides. Some of them are invaluable. Be careful in clean- 
ing coverglasses. There is no excuse for breaking slides and 
coverglasses with the objectives. 


ee 


DRAWING 


‘“‘T can’t draw’’, ‘‘I never could draw’’, or ‘‘I simply cannot 
learn to draw’’, are some of the expressions a teacher of biology 
hears from his elementary students when he enters the laboratory 
for the first period of their work. The students do not seem to 
realize that the teacher has heard this before, and the only thing 
for the teacher to do is to smile and say, ‘‘Oh, yes, you ean”’, 
“We'll teach you how’’, or ‘‘ Well, you do not have to be an 
artist to study biology’’. A student might more profitably say, 
‘“T have never been able to draw, but I wish I could draw, and 
I'll try my best to learn how.’’ The statements above attributed 
to the teacher are essentially true; everybody is able to draw 
more or less and can be taught how if he is willing to try, and 
anyone who takes pains is able to draw well enough to make a 
good record in biology. 

What we are and especially our manner of doing things de- 
pend largely upon our attitude of mind. Since drawing is an 
attempt to represent what one sees, one must constantly bear in 
mind that it must be drawn as it is. This attitude of mind is 
especially necessary in biological drawing, because, above all, this 
type of drawing must be accurate. A student who tries to fol- 
low this suggestion will no doubt make some ludicrous mistakes 
at first, but, as he becomes better able to use the microscope and 
interpret what he sees, his mistakes will gradually be reduced. 
Later on, a little ‘‘idealizing’’ of the drawing may be permissible: 

There are two kinds of drawings in biology : microscopical and 
macroscopical, or sketching. The two types require a different 
technique. Success in the first type of drawing depends largely 
upon ability to use the miscroscope and to interpret what is seen. 

When you look at an object in the microscope, it generally 
looks flat, but very few things are flat.” They appear so because 
you are using only one eye, and the focus of the microscope lies 
in a thin plane. Learn to see things in three dimensions in the 
microscope as elsewhere. Focusing the microscope upon the 
upper, middle, and lower regions of the object will help you to 
do this. 


[8] 


Very few instructors in biology are artists, and those who are 
probably will not attempt to teach art. They can, however, give 
their students some very helpful suggestions which, if observed, 
will improve their drawings very much. 

One of the first things to learn in microscopical drawing is 
how to draw a line, not a straight line necessarily, but just a line. 
Examine the two lines in Figure 2 and decide which is the better. 


FIGcuRE 2 


Why is one better? Because it is of the same width through- 
out. A line ean be drawn so by holding the pen or pencil in the 
same position while drawing it and bearing down evenly. Do 
not twist the pencil while drawing a line. [If all lines have the 
same width throughout their whole length, the appearance of 
your drawing is improved surprisingly. 


[9] 


FIaure 3 





FIGcurE 4 


[10] 


The next point deals with the drawing of two lines. Examine 
a and b in Figure 3. Which is more pleasing? You notice, of 
course, that the drawing that makes the better appearance has 
the two lines parallel. It is surprising how many things in 
nature have parallel lines, and if the lines are parallel they 
should be drawn so. 

A third point to be observed in drawing is illustrated in a 
and b, Figure 4. It will not take you long to decide which is the 
more pleasing. Why? Have you noticed how few things in 
nature have sharp corners and absolutely straight lines? This 
point applies, however, more to habit sketches than to micro- 
scopical drawings. 

In microscopical drawing use sharp, bold lines. Shade as little 
as possible, but, if shading is necessary, use stippling (Figure 5). 

In habit sketching it is well to remember that sharp angles 
and corners should be avoided. Shading the object evenly makes 
it look flat, when, in reality, very few things in nature are 
perfectly flat. 





Figure 5 


NOTES 

Make your notes brief, but explicit. Write down the things 
which are most important. At first this is difficult to determine, 
but you will soon learn what is important and what is not. First 
of all, state in your notes what you have done in the laboratory, 


[11] 


including the purpose of the work, the materials, methods, ob- 
servations, ete. If you are working with any particular plant, 
add a short discussion of its structure and form, habitat, dis- 
tribution, method of reproduction, and any special peculiarity, 
its life history, and its economic importance, if any. Be sure to 
include a diagram of the plant’s life history. This information 
you will get from various sources: lectures, textbooks, reference 
books, talks by the laboratory instructor, and your own obser- 
vations, 


[12] 





PART ONE 


OUTLINE OF PART I 
I. THE UNIT OF STRUCTURE: THE CELL 
1. THe CELL WALL 


2. THE CELL STRUCTURE 
38. THe Living Puant CELu 


II. THALLOPHYTES 
1. THe ALGAE 


a. Cyanophyceae (the blue green algae) 
(1) Oseillatoria 
(2) Nostoe 
(3) Cylindrospermum 


b. Chlorophyceae (the green algae) 
(1) Protoecoeeus 
(2) Chlamydomonas or Sphaerella and Volvox 
(3) Desmids 
(4) Diatoms 
(5) Spirogyra, ete. 
(6) Ulothrix, ete. 
(7) Oedogonium 
(8) Vaucheria 


c. Phaeophyceae (the brown algae) 
(1) Eetoearpus, ete. 
(2) Fucus, ete. 
(8) Padina 

d. Rhodophyceae (the red algae) 
(1) Nemalion 
(2) Polysiphonia 


2. THe FuNGI 
a. Schizomycetes (bacteria) 


b. Phycomycetes 
(1) Saprolegnia (water mould) 
(2) Mueor (bread mould) 


[14 | 


c. Ascomycetes 
(1) Yeast 
(2) Peziza and Morchella 


(3) Aspergillus and Penicillium 
(4) lichens 


d. Basidiomycetes 
(1) Mushrooms, puffballs, ete. 
e. Protobasidiomycetes 
(2) Ustilaginales (smuts) 
(3) Uredinales (rusts) 
III. BRYOPHYTES 
1. Hepaticar (Liverworts) 


a. Riccia 
b. Marchantia 
c. Anthoceros 


2. Musct (Mossss) 


a. Sphagnales (peat moss) 
b. Bryales (true moss) 
IV. PTERIDOPHYTES 
1. FimicaLes (TRUE FERNS) 
2. LycopopiALEs (CuuB Mossss) 
a. Lycopodium 


b. Selaginella 
V. FIELD STUDY 


[15] 


EXERCISE 1 
I. THE UNIT OF STRUCTURE: THE CELL 

The Cell Wall. Obtain a prepared slide of a cross section of 
a stem. Place this on the microscope stage with the side having 
the coverglass upward, so that the section is in the center of the 
opening of the stage or directly below the objective. Using the 
low power (the shorter objective), with the coarse adjustment, 
turn the microscope tube down until the objective is about a 
quarter of an inch from the slide. Then, looking in the micro- 
scope, raise the tube until something is seen. Using the fine 
adjustment, raise or lower the tube until the object is perfectly 
distinct. Move the slide to determine if the compartments are 
all alike. Select a place in the section where the compartments 
have thick walls, and draw a few as accurately as possible. Now 
raise the tube and swing in the high power objective. Lower the 
tube until it almost touches the slide. Again, looking in the 
microscope, raise the tube until something is seen, and adjust 
the focus with the fine adjustment. Study the walls of the com- 
partments and draw a few. Are the walls double or single? 
Why ? 

The Cell Structure. From the instructor obtain a prepared 
slide of a section of a root tip or of some other growing part of a 
plant. Proceed as before, using the low power first. What are 
the differences between these cells and those studied in the stem ? 
Where does the cell wall come from? Of what substance is it 
composed? Using the high power, draw a few cells as accurately 
as possible. 

The Living Plant Cell. Secure a part of a living plant. A 
moss leaf will do. Place it in a drop of water on a slide and 
cover with a coverglass. Study with low and high power. Draw 
a few cells under high power. Is the green color distributed uni- 
formly throughout the cell? What is it called? What are the 
bodies containing the green color called? Do you see any other 
particles in the cell? What are they called? What is the trans- 
parent jelly-like substance in the cell called? 


REFERENCE 
Sharp, L. W., An Introduction to Cytology. 


[16 ] 





EXERCISE 2 


Il. THALLOPHYTES 
1. ALGAE 
a. Cyanophyceae (the blue green algae) 

Oscillatoria. Examine the material with the naked eye. 
Touch it with a needle. Note the color and the structure of the 
colony. Place a small piece of the material on a slide in water 
and cover it with a coverglass. Examine with low and high 
power. Is it made up of one or of many cells? If many, how 
are the cells arranged? What is the shape of the cells in the 
thread? What is the shape of the cell at the tip? Why? Ex- 
amine the thread carefully and determine if all cells are alike. 
You should find some which are empty. These are called 
heterocysts. What important part do they play in the life of 
the plant? Does the plant move? Determine the kinds of movye- 
ments. Draw carefully a few filaments as seen under low power. 
Draw a part of one filament under high power, including the end 
cell and a heterocyst. Plants with this cell arrangement are 
called filamentous. 

Nostoc. Examine and draw colonies of Nostoc. How do 
these colonies differ from those of Oscillatoria? Where does the 
gelatinous substance come from? What is it for? What part 
does it play in the geographical distribution of these plants? 
Mash a small piece of the colony on a slide in a drop of water and 
examine under high power. Draw accurately a complete indi- 
vidual. Where are the heterocysts and how do they differ from 
those in Oscillatoria? 

Cylindrospermum. Study this plant in the same manner as 
those above. Note the differences and resemblances. 


REFERENCES 
West, €. S., Algae, 1; Wolle, F., Fresh Water Algae of the 
United States. 


[18 ] 








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EXERCISE 3 
Il. THALLOPHYTES 


1, ALGAE 
b. Chlorophyceae (the green algae) 

Protococcus. This minute plant occurs on the shady side of 
trees, fences, and buildings, forming a characteristic green cov- 
ing, which is especially evident in damp or rainy weather. Ex- 
amine with the naked eye a piece of bark having this plant on it. 
With a knife or a needle carefully scrape off a little of the green 
substance on a slide in a drop of water, being careful to get as 
little of the bark as possible with it. Cover with coverglass and 
examine with low and high power. What is the shape of the 
plant? Is it a one-celled or a multicellular individual? How 
do you know? Is it motile? How does this plant reproduce? 
Look for a single plant and draw it carefully under high power. 
Notice the following parts: cell wall, chloroplast, nucleus. If 
you have difficulty in seeing the nucleus, add a drop of eosin on 
the side of the coverglass and draw it under with a blotter. 
Make drawings of at least four stages in the reproduction of this 
plant. 


Protococcus is supposed to be the simplest of all plants. What 
does this mean? It does not necessarily mean that it is the most 
‘‘yrimitive’’. What is your conception of the most primitive 
plant? Why? 

This plant belongs to a group of plants characterized by 
non-motile vegetative cells. The reproductive cells, if any, may, 
however, be motile. Other forms in this group are: Scenedesmus, 
Pediastrum, and ‘‘ Water-Net’’ or Hydrodictyon. If available, 
examine these and make habit sketches. 


REFERENCE 


Coulter, J. M., Barnes, C. R., and Cowles, H. C., Textbook of 
Botany, I. 


[ 20 ] 








EXERCISE 4 


Il. THALLOPHYTES 
1. ALGAE 
b. Chlorophyceae (Continued ) 

Sphaereila. This microscopial plant occurs frequently in de- 
pressions in pure limestone rocks or marble. It is most easily 
collected from depressions in marble monuments or tombstones. 
When dry, it appears as an encrusted red layer. 

In some regions, especially in colder climates, it grows on 
ice and snow and has been named ‘‘red snow’’. In order to 
get the most desirable stages of this material, it is best to serape 
off some of the encrustations and put them in rain or pond 
water in the evening. The following morning the material 
should be in the best condition, which means that almost all 
stages in the life history of this plant are represented. 

Put a drop of the liquid on a slide and cover with a cover- 
glass. Examine with low power and try to locate the small moy- 
ing bodies. Since this is a motile plant it is rather difficult to 
study. After finding it with high power and after having deter- 
mined its motility, put a small amount of iodine on the side of 
the coverglass. This will make it more easily seen and studied, 
heeause it will remain stationary and will be slightly colored. 

Make drawings of the vegetative cell showing cilia, the trans- 
parent sheath, the protoplast with its ‘‘eye spot’’. What is this 
red spot supposed to be for? Search for those which are divid- 
ing into smaller ones. What kind of reproduction is this? How 
does this method differ from the method in Protococcus? 

In the material, you should also find spherical cells with a 
thick wall and colored red. This is called the encysted stage and 
is the condition the plant assumes under unfavorable conditions 
such as drought, heat, the presence of unfavorable substances, ete. 

Volvox. This is a good example of what is called a colonial 
form. All the cells making up this plant resemble Sphaerella. 
Make a drawing of the plant showing form, individual cells. and 
the young colonies inside of the sphere. How does this plant 
reproduce? Does it show specialization ? 


REFERENCES 
West, Algae, I; Wolle, Fresh Water Algae of the United 
States; Coulter, Barnes, and Cowles, Textbook of Botany, I. 


[ 22 





EXERCISE 5 
Il. THALLOPHYTES 


1. ALGAE 
b. Chlorophyceae (Continued ) 

Desmids. These are fresh water unicellular forms which, be- 
cause of their sexual reproduction, resembling that of Spirogyra, 
belong to the same group called the Conjugales. With a pipette, 
put a drop of water containing desmids on a slide and cover 
with a coverglass. Examine with low power. Notice the oblong 
and more or less curved shape. Notice also that the cell seems 
to be divided into two equal halves. Study them under high 
power. Notice the large green chloroplast in each half. Notice 
also the pyrenoids on this. Try to determine the shape of the 
chloroplast. Look for the nucleus in the center of the cell. Ex- 
amine the end of the plant. Notice the clear globule with the 
small bodies in motion. Make an accurate drawing of one des- 
mid. If the material is abundant, you should find stages of cell 
division. Draw as many of these stages as you find, including a 
newly formed desmid. If material is available, draw conjugation, 
zygospore, and other desmids. 

Diatoms. These are unicellular plants which occur in both 
fresh and marine waters. They are not closely related to des-. 
mids, but are included here because they are usually found with 
them and have the same method of sexual reproduction. Notice 
the rectangular shape. This is the side view. Under high power, 
draw carefully this view showing the lines which are the edges 
of the two halves of the wall, which come together like two halves 
of a pill box. Try to find one turned so that it has a more ob- 
long shape. This is called the valve side, while the former is 
called the girdle side. What is the coloring matter in these 
plants? Do they move? If so, how? Since the cell walls are 
made of very hard substance, the protoplast is not able to break 
them. How does it reproduce by cell division? Draw stages 
showing cell division. In this mode of cell division what peculiar 
result is obtained? Does this plant have sexual reproduction? 
Examine diatomaceous earth and draw as many different forms 
of shells as you can find. This earth is simply an accumulation 
of shells of diatoms that lived ages ago. It is sometimes used 
as a cleaning powder. 


[ 24 ] 


THALLOPHYTES 


REFERENCES 

West, Algae, I; Wolle, F., Desmids of the United States; 
William, H., Fresh Water Algae of Connecticut; Mann, A., 
Diatoms; Wolle, F., Diatomaceae of North America. 


EXERCISE 6 
II. THALLOPHYTES 
1. ALGAE 
b. Chlorophyceae (Continued ) 

Spirogyra. This is a floating form which occurs in fresh 
water pools and ponds. If possible, examine it in its natural 
habitat. Examine it close with the naked eye and with a mag- 
nifying glass. Leave some of it in the sun for an hour and ex- 
amine again. Compare this with some which has been left in the 
dark. What difference do you observe? What causes the bub- 
bles of gas to appear? What is this gas? Put some of the fila- 
ments under low power and examine. Why is it called Spiro- 
gyra? What are the green spiral bands? What are the ‘‘but- 
tons’’ on this band? Note the nucleus in the center of the cell 
suspended by strings of cytoplasm. Examine under high power, 
and draw accurately one cell showing all the parts of the cell. 
From living, preserved material or prepared slides, study repro- 
duction. Select first a stage in which the dark round or oval 
bodies are fully formed. Notice that these are found in one of 
two filaments which are united by tubes in parallel. What do 
you suppose has taken place? What are the dark bodies called? 
Study and draw as many stages as you ean find in the formation 
of the zygospore. The union of two cells is called conjugation. 
This is a form of fertilization and is the essential fact which 
makes reproduction sexual. Each cell is then called a gamete. 
When the gametes look alike, we eall the reproduction isogamous ; 
when unlike, heterogamous. Which is this? What part of the 
cell acts aS a gamete in Spirogyra? Are the gametes exactly 
alike? If all the protoplasts from one filament go into another, 
what does this probably mean? Does Spirogyra reproduce 
asexually ? 

Other plants closely related to Spirogyra are Zygnema, Zygo- 
gonium, and Mougeotia. The second one is like the first, except 
that the zygospores are formed in the tube between the fila- 
ments. Examine and make sketches of these if available. 


REFERENCES 
West, Algae, I; Wolle, Fresh Water Algae of the United 
States. 
[ 26 ] 





EXERCISE 7 
II. THALLOPHYTES 


1. ALGAE 
b. Chlorophyceae (Continued) 

Ulothrix. Examine fresh or preserved material with the 
naked eye. These plants occur attached on rocks on the edges 
of lakes and in streams or where the water is in constant motion. 
Mount a small portion of the material in water on a slide; cover 
with a coverglass, and examine as before. What kind of a plant 
is this one? What is the shape of the chloroplast? This is an 
attached form. How is it attached? Make a careful drawing of 
the filament showing the holdfast cell. This plant shows in the 
holdfast cell specialization and some differentiation. What do 
these terms mean? If you have living material, study zodspore 
formation and their germination. What is a spore? A zodspore? 
Sometimes two of these cells fuse, acting as gametes, and sexual 
reproduction takes place. What are gametes, and what is sexual 
reproduction? From prepared slides draw a few cells, under 
high power, showing zodspore or gamete formation. 

Cladophora. How does this form differ from Ulothrix? Note 
especially the branching habit and number of nuclei in each cell. 
This is said to be partly coenocytic. What does this mean? 
Make a drawing of a part of the plant, including the tip, showing 
the mode of branching and nuclei. 

Other forms in this group are: Ulva or sea lettuce (a marine 
form), Chaetophora, and Stigeoclonium. If available, and you 
have time, make sketches of these. 


REFERENCES 


West, Algae, I; Collins, F. S., The Green Algae of North 
America. 





EXERCISE 8 


II. THALLOPHYTES 
1, ALGAE. 
b. Chlorophyceae (Continued ) 

Oedogonium, This is an unbranching, filamentous form usu- 
ally found in stagnant or slightly moving fresh water. The 
peculiar things about this plant are, its method of growth and 
its method of sexual reproduction. Examine fresh material if 
available and notice the shape of the cells and the chloroplast. 
This chloroplast is said to be reticulate. On some cells you will 
notice rings on one end. These are the edges formed when the 
cells divide. The instructor will explain this mode of division. 
Draw carefully a cell of this plant. Draw also a cell having the 
‘“‘rings of growth’’. From preserved material study sexual re- 
production. In this plant the gametes are different (hetero- 
gamy). This means that the sex cells have become highly special- 
ized and differentiated. The female gamete is called the egg, 
and the male gamete the sperm. Both may occur in the same 
filament (monoecious) or in separate filaments (dioecious). The 
cell which includes the egg is called the odgonium, while the eell 
which contains the sperms (two in this case) is called the sperm- 
ogonium or antheridium. The difference in the gametes is in the 
size and motility. The egg is large and stationary, while the 
sperm is small and motile. Draw an o6gonium showing the thick 
wall and the egg and the opening where the sperm entered. This 
has been fertilized and is therefore an odspore. An odspore is 
simply, then, a special zygospore. Either may be called a zygote. 
Look for antheridia and draw, showing the number of sperms in 
each cell. 

Asexual reproduction is brought about by large zoospores. 
These resemble eggs, except that they are motile, having a crown 
of cilia at one end just ike the sperms. When the odspore germi- 
nates, it produces four zodspores, which give rise to new plants. 
If material is available, study young plants which have come 
from zoospores and draw. Note the holdfast cell. What is its 
function? What relation does it have to habitat? 

REFERENCES 

West, Algae, 1; Collins, The Green Algae of North America; 

Coulter, J. M., Evolution of Sex in Plants. 
[ 30 ] 





[ 31] 





EXERCISE 9 
Il. THALLOPHY TES 
1. ALGAE 


b. Chlorophyceae (Continued ) 


Vaucheria. This is often called ‘‘green felt’’ because of its 
dark green felt-like appearance when seen on the edge of streams, 
on the bottom of ponds and streams, or sometimes floating. Ex- 
amine some living material with the naked eye and with a mag- 
nifying glass. Can you make out the shape of the plant with 
the naked eye or with the magnifying glass? This is one of the 
largest of fresh-water algae. Examine some under low power 
and draw a piece showing branching. Do you find any cross cell 
walls? What is such a plant called? Study the inside of the 
tube and draw a piece of it showing chloroplasts, fat globules, 
and nuclei. If the latter are hard to find, examine a prepared 
slide. Examine some material which has been submerged in 
water over night. Notice the large swellings. These are the 
zoospores. Search for some of these bodies which are germinat- 
ing and draw. These zodspores have many nuclei and many cilia. 

From the proper material, study sexual reproduction. Look 
for dark green oval shaped organs. These are the odgonia. Near 
them you should find the antheridia. Draw these two organs very 
carefully. Notice that the walls have formed below the o6gonium 
and across the antheridium. 


In some forms there are many od6gonia around one antheri- 
dium, all terminating a special branch. The odspore germinates 
into a new plant directly. 

A closely related plant to this one, as small green spheres 
about the size of a pin head, is often seen on moist ground near 
streams. This is called Botrydium. If material is available, 
examine and draw one. 

REFERENCES 


West, Algae, I; Collins, The Green Algae of North America. 


[ 32] 





[33] 





EXERCISE 10 
Il. THALLOPHYTES 
1. ALGAE 
c. Phaeophyceae (the brown algae) 

The brown algae are almost all marine. They oceur on all 
seacoasts, but are more abundant in the cooler waters. Most of 
them are large thallose plants, some of which reach large dimen- 
sions. 

Ectocarpus. Put some of the preserved material on a slide 
and examine under low power. What plant of the green algae 
does it most resemble? Make a habit sketch of part of the plant, 
including the tips of the branches. Note where the branches 
come off. Note also the dark, dense bodies. Are they made up 
of one or of many cells? These are the gametangia. What do 
they produce? Is this plant isogamous or heterogamous? Make 
a careful study of the development of these organs. Make draw- 
ings of at least five stages, including the youngest you ean recog- 
nize as a gametangium and the oldest. This plant has also 
sporangia. If material is available, study and draw these also. 


Examine herbarium specimens of other brown algae belong- 
ing to this group. Make habit sketches of Laminaria, Macro- 
cystis, and others. These forms are isogamous and are therefore 
classed together in the order Phaeosporales. 


REFERENCES 


Coulter, Barnes and Cowles, Textbook of Botany, 1; Arnold, 
A. F., The Sea-Beach at Ebb-Tide. 


[ 34] 





EXERCISE 11 


Il. THALLOPHYTES 
1. ALGAE 


c. Phaeophyceae (Continued ) 

Fucus. Make a macroscopical examination of this plant. Note 
the holdfast organ (the rhizoids), the stipe, and the long branch- 
ing lamina or blade. Note the peculiar branching. This is called 
dichotomous. Note also the swellings on the blade and at the 
tips of some of the branches. These swellings are of two kinds; 
those at the tips hold the reproductive organs and are called 
receptacles; those on the blades lower down are simply air blad- 
ders, or floats, which help to hold the plant up in water. These 
plants are marine, occuring in the tidewater zone on rocky shores. 
in the cooler waters. Make a good habit sketch of the whole 
plant, including the rhizoids, stipe, blades, floats, and receptacles. 
From prepared slides, make a diagram of a cross section of the 
receptacle showing the pits or conceptacles. The receptacles are 
either male or female. Under low power make a diagram of the 
male conceptacle showing the paraphyses and antheridial 
branches. Make, likewise, drawings of the female conceptacles. 
showing odgonia and paraphyses. Under high power, draw an 
antheridium showing sperms and an odgonium showing eggs. 

If living material is available, observe the demonstration of 
fertilization in this plant and make a sketch of it. 


Sargassum. Sargassum is a form which resembles Fucus, ex- 
cept that it is usually found floating in the ocean, especially in 
the Caribbean sea (Sea of Sargasso), after which the plant is 
named, and the Gulf Stream. Make a sketch of it. 


REFERENCES 


Coulter, Barnes and Cowles, Textbook of Botany, 1; Arnold, 
The Sea-Beach at Ebb-Tide. 


[ 36 ] 








EXERCISE 12 
Il. THALLOPHYTES 


1. ALGAE 
c. Phaeophyceae (Continued ) 

Padina. Make a study of this plant from preserved material 
or from herbarium sheets. Notice that there are three plants on 
each sheet. Do you see any essential differences between them ? 
Although they may look alike, microscopical examination shows 
that they are all different. Make a habit sketch of one of them. 
Also examine preserved material. This plant is a marine form, 
whose life history has been worked out recently and it is there- 
fore not usually discussed in the textbooks. Its life history, how- 
ever, resembles Dictyota, which is discussed in the more advanced 
books. From the instructor, secure pieces of the preserved ma- 
terial. Place these on the slide in a drop of water. In the study 
of the whole plant, you should have noticed dark lines or zones. 
These are where the reproductive organs occur. Make sketches 
of the antheridia, o6gonia, and sporangia under high power. 

Why does this plant appear in three different kinds? The 
explanation is this: This plant illustrates a thing very common 
in the higher plants, known as ‘“‘alternation of generations’’. That 
means that there are two generations in the life history of.this 
plant, alternating with each other. One of the generations is 
sexual, and the other is asexual. Consequently, we find two kinds 
of plants, the sexual and the asexual. But it happens that in this 
plant the male and female gametes are produced on separate 
plants, hence there are three kinds. When the egg is fertilized, 
it does not develop into male or female plants, but develops into 
a plant which has no sex. This plant does not produce antheridia 
and odgonia, but sporangia. When the spores germinate, they 
produce male and female plants, and the life history is completed. 
What resemblances does this plant show to Oedogonium? Just 
how do the two differ in their life histories? Would you econ- 
clude that Oedogonium has alternation of generations? 


REFERENCES 


Wolfe, J. J., ‘‘Alternation and Parthenogenesis in Padina,”’ 
Journal of Elisha Mitchell Scientific Society, XXIV. 78-109. 
(1918) ; Strassburger, E., Textbook of Botany, (5th Ed.). 


[ 38 ] 





EXERCISE 13 
II. THALLOPHYTES 


1, ALGAE 
d. Rhodophyceae (the red algae) 

These plants are almost all marine, occurring in the warmer 
waters and at greater depths than the browns. Most of them 
have a red color in addition to the chlorophyll, which is entirely 
masked. While red color is common to the majority of these 
plants, and most of them live in the sea, there are some which 
are green and live in fresh water. The best distinguishing char- 
acteristic is the reproduction, which is extremely complex. 

Nemalion. This is one of the simpler of the red algae. Study 
prepared slides. Note whether it is simple or branching, fila- 
mentous or thallose. Study the tips especially. Make a drawing 
showing the method of branching. Also make drawings showing 
antheridia, procarp with carpogonium and trichogyne, and cys- 
tocarp with carpospores. 

Polysiphonia. Make a sketch of this plant from herbarium 
sheets. Note the branching habit and rhizoids or holdfast. Mount 
some of the preserved material on a slide and examine. Is it fila- 
mentous or thallose? How does it branch? Why is it called 
Polysiphonia? How many plants are there in the life history? 
Does it have alternation of generation? Make a drawing of a 
male plant, including the tip so as to show antheridia, a female 
plant showing procarp, a female plant showing cystocarp and 
carpospores, a tetraspore plant (sporophyte) showing tetrads. 


REFERENCE 
Coulter, Barnes and Cowles, Textbook of Botany, I. 


[ 40 ] 





EXERCISE 14 


II. THALLOPHYTES 
2. FuNeI 
a. Bacteria 

Expose agar plates to air for one or two hours. Leave one 
plate unexposed. These plates are sterile, which means that 
there is not a single living organism in them before they.are ex- 
posed. After they are left in the incubator at thirty-seven de- 
grees Centigrade (ninety-eight degrees F') until the next period, 
examine them again. Notice the spots formed. These are 
colonies of bacteria composed of millions of organisms. Count 
the total number of different colonies and the number of each 
kind. Make a sketch of each different colony. Study the differ- 
ent colonies and see how they differ. Make notes of this work. 

With a needle, remove a small amount of a colony and stir in 
a drop of water on a dry slide. Cover with a coverglass and 
examine with a microscope. Can you see anything under low 
power? Do the bacteria move? Distinguish between Brownian 
movement and actual movement by the bacteria. How do bac- 
teria move? Under high power, determine the shape and size of 
the individual organisms. Determine how they are grouped, 
whether in chains or in masses. Also examine a colony under 
low power. Can you make out the individual organisms? Ex- 
amine the bacteria of several different colonies as above. Make 
notes and sketches. 

From prepared slides, make drawings of the principal types 
of bacteria. If preparations showing cilia and spores are avail- 
able, study and make sketches of these. 


If slides of disease (pathogenic) bacteria are available, ex- 
amine them. 
REFERENCES 


Marshall, C. E., Microbiology; Vallery-Radot, R., Life of 
Pasteur. 


[ 42 ] 





EXERCISE 15 
II. THALLOPHYTES 


2. FuNGr 
b. Phycomycetes 


Saprolegnia. This fungus is usually called water mould, 
because it is found growing on insects or other bits of organic 
matter floating on water from ditches, ponds, and wells. It is 
seldom that one finds enough of it in nature to make a study of 
it. Consequently, the best thing to do is to grow it in the labor- 
atory. The methods commonly used are as follows: Collect a 
number of insects, such as flies, bugs, ete., and throw them on 
water which has been collected from a ditch, pond, or stream. 
The water should be put in a flat dish, and it is better to cover it. 
After a day or two, you should find a cobweb growth on the 
insect. A better way is to boil some starchy corn, cut the grains 
up into small bits with a sterilized scalpel, and throw these into 
the water with sterile forceps. 

Make a macroscopical study of the growth and sketch it. 
What type of plant is it? Place a whole growth in a small flat 
shallow dish in water and examine with low and high power. 
Notice whether the hyphae are septate. Make drawings of the 
hyphae. If you have the proper stage you should see sporangia. 
These are the walled-off ends of the filaments. Make drawings of 
a mature sporangium and an empty one. Are the spores motile 
or not? Draw some. This is the asexual method of reproduc- 
tion and is the one which usually comes first. Sexual reproduc- 
tion may be seen in the older growths. You should find oégonia 
with several eggs in them and antheridia near them. How is 
fertilization brought about in this plant? Make careful draw- 
ings of the sex organs. Which algae does this plant resemble 
from its method of reproduction? 


REFERENCE 


Coker, W. C., Saprolegniaceae. 


[ 44] 





II. THALLOPHYTES 
EXERCISE 16 
2. FUNGI 
b. Phycomycetes (Continued ) 

Mucor. This plant is commonly found on moist bread and is 
therefore usually called Bread Mould. It differs from bacteria 
and yeast in that it is filamentous and in this respect resembles 
some of the algae. To obtain Mucor, take a piece of bread and 
either leave in open air for several hours or throw it on the floor 
in places where considerable dust has accumulated. Then place 
it on some support above a dish of water and cover with a bell 
jar or something which is practically air tight. This will make 
a moist chamber. Then leave in a moderately warm place for 
a day or two. 

If you have been successful, you should find the bread cov- 
ered with a cobweb-like growth. Examine it carefully with the 
naked eye. Notice the color. What color substance does this 
lack which was found in the algae? What effect must this have 
upon its food relation? What kind of food does this plant use? 
Where did this food come from originally? How was this food 
prepared? Substances like these, which are produced by living 
organisms, are called organic. If the substance is used for food, 
it is called an organic food. Fungi like Mucor, which grow on 
dead organic substances, are called saprophytes, and this life re- 
lationship is called saprophytism. If possible, examine the plant 
with a magnifying glass. Notice the knob-like structures termi- 
nating the filaments. These are the sporangia. When they are 
mature, they are black. The filaments are collectively called the 
mycelium. 

Place a small amount of the plant on a slide in a drop of 
weak solution of aleohol. Examine under low power. Do you see 
any cross walls in the filament? What is such a plant called? 
What plants in the algae does it resemble in this respect? Study 
the lower part of the plant. Notice the root-like structure which 
anchors the plant to the bread. This is called the rhizoid, be- 
cause of its resemblance to a root. Notice the sporangium. 
Make a drawing of the plant showing the mature sporangium, 


[ 46 ] 


THALLOPHYTES 


the filament, and the rhizoid. From a broken sporangium, ob- 
tain spores. Examine and draw. Also draw a sporangium. 
What is the columella? 

Place some spores on the surface of a sugar solution in a 
covered petri dish and leave for twenty-four hours. Examine 
and draw germinating spores. Where are spores usually found 
in nature? 

From prepared slides, make a study of sexual reproduction. 
Notice the large, dark bodies. These are the zygospores. Try to 
determine how they are formed and draw several stages in their 
formation, including the mature stage. If the zygospore germi- 
nates, what does it give rise to in this form? Is this plant 
differentiated into sexual individuals? What is meant by plus 
and minus strains? Why is it not possible to tell which is male 
and which female? 

REFERENCE 


Coulter, Barnes and Cowles, Textbook of Botany, I. 


[47 ] 


EXERCISE 17 
II. THALLOPHYTES 


2. Funai 
c. Ascomycetes 

Yeast. Put a small piece of Fleishman’s yeast in a flask con- 
taining grape juice or a solution of sugar. Mix well, stopper the 
flask with cotton, and leave in the incubator at thirty degrees 
Centigrade for twenty-four hours. Note the scum formed on top 
and the sediment on the bottom of the flask. Explain. Put a 
small amount of the sediment on a slide and examine under low 
and high power. What kind of an organism is yeast? Notice the 
method of reproduction. This is simple cell division, but it is 
ealled ‘‘budding’’. Under high power, draw a single organism 
showing the vacuole and nucleus. The nucleus can not be seen 
unless you add a drop of some coloring matter like eosin. Draw 
several stages in the production of new eells. Look for the 
different kinds of yeast. How do they differ? Make sketches of 
the different kinds. 

Put some of the yeast solution in a wide-mouthed bottle, stop- 
per, and leave for twenty-four hours. The stopper should have 
a funnel in it that can be closed and an outlet tube. Place the 
outlet tube in a solution of calcium hydroxide (lime water) or 
barium hydroxide. Pour water in the funnel. Open the funnel 
so that the water will drive out the air into the lime water. What 
happens? Explain. Blow air into some of the same solution. 
What happens? What is the resemblance between respiration 
and yeast fermentation? What are the two substances formed 
by yeast? From what are they formed? How does the yeast do 
it? What is the purpose of the process? In your notes explain 
the industrial uses of yeast and why it is used in these industries. 

The fungi included in this group are characterized by a spor- 
angium ealled an ascus. This structure resembles a sac, so the 
fungi are often called the sac fungi. The ascus is the walled-off 
end of a hypha slightly enlarged and contains a certain number 
of spores. These asci usually occur in a layer in some part of the 
plant together with some sterile hyphae, the paraphyses. This 
layer is called the hymeniwm. Since yeast very seldom produces 
this, it is not typical. We usually study as typical Ascomycetes, 
Peziza and Morchella. 

[ 48 ] 


THALLOPHYTES 


REFERENCES 


Marshall, Microbiology; Guilliermond, A., The Yeasts (Tr. 
by F. W. Tanner) ; Effront, J., Enzymes and Their Application, 
(Tr. by 8. C. Prescott); Bayliss, W. M., The Nature of Enzyme 
Action. 


[ 49 ] 


EXERCISE 18 
II. THALLOPHYTES 
2. FUNGI 
c. Ascomycetes (Continued ) 

Peziza. The pezizas are commonly called ‘‘eup fungi’’, be- 
cause the part of the plant above the substratum is cup-like. 
These plants are saprophytic, growing on dead branches and 
twigs in moist situations in the woods. Remember that what 
you are studying is only the part above the substratum which 
is associated with the production of spores. It is therefore called 
the sporophore. The vegetative mycelium is usually very ex- 
tensively distributed throughout the substratum. Sinee this 
sporophore produces ascospores, the whole structure is called an 
ascocarp. 

Make habit sketches of the cup-like ascocarp. With a sharp 
knife, remove a small amount of the inner lining of the eup 
(ascocarp), put it on a slide in a drop of water, and mash with a 
cover-slip. If you find the asci, what is this lining called? Draw 
an ascus. How many spores does each ascus have? Look at the 
vegetative part of the sporophore. Is this a filamentous plant? 
From prepared slides, draw a section of a hymenium. 

Morchella. This is called morel and is edible. It grows up 
from the ground in moist woods. Draw one. What is this part 
of the plant called? Where do you suppose the asei are? Re- 
move a small part of the inside of a depression and study under 
the microscope. Do you find the asci? Make drawings of them. 

The Ascomycetes are of great economic importance because 
of the injury they do to some of our economic plants. The com- 
mon mildews so pernicious to many shrubs, such as roses and 
lilacs, belong to this group. Examine leaves of rose or clover 
infected with powdery mildew. Examine the surface with the 
low power. With a sharp knife, scrape off some of the hyphae 
on a slide in a drop of water; examine with low and high 
power. Are the hyphae septate? How are the spores produced ? 
What are these spores called? If ascocarps are present, study 
them also. 

REFERENCE 
Coulter, Barnes and Cowles, Textbook of Botany, I. 


[ 50] 





EXERCISE 19 
Il. THALLOPHYTES 


2. Funai 
c. Ascomycetes (Continued) 

Aspergillus. This is sometimes called Black Mould because 
of the black spores which it produces. This mould is common 
on cheese and on bread associated with Mucor. The best way to 
obtain the mould is to prepare plates of glucose agar and expose 
them to air for an hour or two. After twenty-four hours in the 
incubator, look for mould colonies, which you will readily recog- 
nize by their cobwebby appearance. After forty-eight hours, the 
colony should begin to turn black on top, which means that the 
spores are being produced. 

Examine some of this mould in a weak solution of alcohol. 
The alcohol will evaporate rapidly, so you will have to see to it 
that it does not dry up. Ask yourself the following questions: 
How does this mould differ from Mucor? Is this also coenoeytic? 
Does it have rhizoids? How are the spores produced? What are 
such spores called? What is the organ which produces the spores 
called?) What are the spores produced in this way called? Make 
accurate drawings of the filaments (hyphae), conidiophore, cont- 
diospores, and several stages in the development of the conidio- 
phore. If necessary, use prepared slides. Sow some spores 
on a weak sugar solution and incubate. After twenty-four hours, 
examine and draw several stages in germination. This plant also 
reproduces sexually. If material is available, study this method 
of reproduction. 

Penicillium. Blue or Green Mould. This is the most com- 
mon mould on cheese. It can be obtained, however, by the same 
method as that used in obtaining Aspergillus. Its reproduction 
is very much like that of the latter. Proceed as with Aspergillus. 
What are the differences between the two plants? What are the 
economic uses of these moulds? Why? 


REFERENCE 
Harshberger, J. W., Mycology and Plant Pathology. 





EXERCISE 20 
II. THALLOPHYTES 
2. FUNGI 
c. Ascomycetes (Continued ) 

Lichens. A lichen is not a plant, although it is generally con- 
sidered one. It is usually a growth consisting of two plants, 
which are more or less interdependent. Consequently, a lichen 
may be more correctly defined as a life relationship. The two 
plants composing a lichen are a fungus and an alga. The rela- 
tionship has usually been considered of mutual benefit, but some 
authorities consider the fungus as a parasite on the alga. If the 
former is true, the life relationship is symbiosis; if the second 
theory is correct, the relationship is parasitism. The reason for 
studying lichens at this time is that the fungus present in lichens 
is, with one or two exceptions, an ascomycete. The algae present 
are the unicellular green algae or the blue-green. Lichens are 
common on rocks and on the bark of trees where life conditions 
are more or less severe. They are the first plants to grow on 
bare rocks. 

If possible, make a short field trip to where trees and exposed 
rocks are found. Try to determine the difference between lich- 
ens growing on trees and those growing on rocks; also see how 
many different kinds of lichens you ean find. 


Lichens are classified roughly into three kinds: crustose, foli- 
ose, and fruticose. From a number of specimens in the labor- 
atory, determine to which class each belongs. Make habit sketches 
of each type and note where each one would be found. From a 
powdery lichen, which has been kept in a moist chamber over 
night, scrape a few particles on a slide in a drop of water or 
weak alcohol. Cover with a coverglass and examine under the 
microscope. Is the fungus filamentous? What type of plant is 
the alga? Make drawings from high power of hyphae and algae 
showing the relationship to each other. It is sometimes profitable 
to color the slide with eosin, which will color the fungus red. Do 
the hyphae have cross walls (septate) ? 


If the fungus is an ascomycete, how does it reproduce? On 
some lichens you will find cup-like structures. What are they? 
If the cup is small enough, remove it with a needle and place it 


[ 54] 


THALLOPHYTES 


under a drop of water on a slide. Crush and cover with a cover- 
glass. Examine for spores and sporangia. What are these 
sporangia called? What are the spores called? Make a draw- 
ing from high power of an ascocarp with spores. Determine how 
many spores in each aseus and whether the spores are ‘‘single’’ 
or ‘‘double’’. If the eup is large, scrape off a piece of the inner 
lining of the cup and proceed as above. - 

How does the alga reproduce? This can be determined while 
making a study of the relationship between the fungus and the 
alga. Make drawings of this process. 


REFERENCES 


Fink, B., Lichens of Minnesota; Hasse, H. E., Lichen Flora of 
Southern California. 


[ 55 ] 


EXERCISE 21 
Il. THALLOPHYTES 


2. Funai 
d. Basidiomycetes 

The fungi included under this group are, like the Ascomy- 
cetes, distinguished by a peculiar sporangium ealled a basidium. 
The part which you are studying and which we usually eall 
“‘mushrooms”’ is only the part of the plant associated with the 
production of spores. It is therefore a sporophore. The vege- 
tative part of the mycelium is distributed throughout the sub- 
stratum and is therefore out of sight. It is mould-like and is 
composed of branching filaments (hyphae). ‘Typical Basidio- 
mycetes usually grow on the ground, living on dead organic mat- 
ter such as dead branches, stumps, ete. Such plants are, of 
course, saprophytic. Several are parasitic or partly so, growing 
on living plants, which they destroy sooner or later. The bas- 
idium is a sae-like structure, the walled-off end of a hypha, which 
produces usually four spores. These spores are, however, pro- 
duced on the outside on special projections, the sterigmata, and 
are called basidiospores. 


Mushrooms. Make a habit sketch of a gill mushroom. The 
‘‘oills’’? are the blade-like structures hanging from under the 
eap. The stalk is called the stipe; the cap is called the pileus; 
and the ring on the stipe (if present) is called the annulus or 
velum. All gill mushrooms belong to the family Agaricaceae. 
Mash a piece of a gill on a slide, examine with a microscope, and 
draw spores under high power. Note their shape and outline. 
If there is a “‘cup”’ at the base of the stipe, it is called the volva. 
If material is available, draw several stages in the development 
of the mushroom. There are other mushrooms which do not 
have gills, but have pores instead, the inside of which is covered 
with spores. Make a sketch of one of these. From prepared 
slides of cross sections of gills, make drawings showing the struc- 
ture, including basidia and basidiospores. 

Puffballs. These Basiodiomycetes are called Gasteromycetes. 
Make a habit sketch of one. Notice the hard outer coat, the 
peridium. Where are the spores produced ? 


[ 56 ] 


THALLOPHYTES 


The Earth Star. This is one of the puffballs called Geaster. 
It can not very readily be distinguished from an ordinary puft- 
ball until it is mature. Then the outer coat splits like that of an 
orange when peeled. Upon drying, this skin turns back towards 
the ground and tears the plant loose from the substratum. When 
the wind blows it about, it turns over, and the spores are dis- 
tributed through the opening. 


Bird-Nest Fungus. The technical name for this peculiar 
Gasteromycete is Nidularia. Draw several stages in the devel- 
opment of this plant including a mature one. What is the 
“‘nest’’?? What are the ‘‘eggs’’? Remove an ‘‘ege’’, place on 
a slide in a drop of water, and crush. Examine and draw a 
spore. 

REFERENCES 

Atkinson, G. F., Mushrooms; Mellvaine, C. and Macadam, R. 
K., One Thousand American Fungi; Marshall, N. L., The Mush- 
room Book. 


EXERCISE 22 
II. THALLOPHYTES 
2. FUNGI 
e. Protobasidiomycetes 

Ustilaginales. These are the so-called smuts. They are para- 
sitic Basidiomycetes found on a great number of plants, espe- 
cially the grasses. Since many of the grasses are among our 
most widely cultivated plants, this fungus is of great economic 
importance. It is common on oats, wheat, and corn. In corn 
it may occur in the tassel, on the ear, or in any part of the plant. 
Its usual occurrence is in the ovule (young seed), which becomes 
very much distorted and, when mature, is filled with black spores, 
often called ‘‘brand spores’’. 

Study smutted wheat, oats, or corn. Make drawings of dis- 
torted seeds and of normal seeds for comparison. Also draw 
distorted flowers (male) from the tassel of corn and normal flow- 
ers. Place some spores on a slide in a drop of water, examine, 
and draw. If time permits, germinate spores in a sugar solution 
and draw. It is in connection with the germination of the spore 
that the basidium is produced. This is a short septate filament, 
which usually produces four spores, the basidiospores. 


Uredinales. These fungi are commonly ealled rusts. They 
are also parasitic Basidiomycetes and attack a great variety 
of plants both wild and cultivated. These plants have the most 
complex life history of all fungi. The outstanding peculiarity 
of many of the rusts is that they require two different hosts on 
which to complete their life histories. 


The rust which is most common in this part of the country is 
apple or cedar rust. The two kinds of hosts that this has are 
the red cedar and various species of plants belonging to the 
same family to which the apple belongs. Make a study of a 
cedar apple in autumn condition and sketch. This is a gall pro- 
duced by the fungus. Study this growth in spring condition 
and draw. Remove one of the gelatinous protrusions and mount 
on a slide. Study and make drawings of the spores. What are 
these spores called? When these ‘‘spores’’ germinate they pro- 
duce two basidia, which resemble the basidium of the smuts. 
Study leaves of the apple infected with rust. This is the sum- 


[ 58 ] 


THALLOPHYTES 


mer condition of the fungus. This is called the cluster cup stage, 
and the spores produced are called aecidiospores. Make a simi- 
lar study of wheat rust. 

Study straw and leaves of wheat with ‘‘black rust’’. Scrape 
off some of it and study under the microscope. What are these 
spores called? This is the autumn or winter condition of the 
rust. Study leaves of the common barberry bush and draw. 
Study spores and draw. What are these spores called, and what 
is this stage? From the barberry, the spores go on the wheat. 
This takes place in the early summer. There it develops red 
rust spots. Examine these and draw. Remove some of the 
spores and examine under the microscope. These spores are 
called uredospores. Is this stage present in the apple rust? 
Compare the stages and respective hosts in the two rusts. 


REFERENCES 
Duggar, B. M., Fungus Diseases of Plants; Stevens, F. L. and 
Hall, J. G., Diseases of Economic Plants; Stevens, F. L., Fungi 
Which Cause Plant Disease. 


[ 59 J 


EXERCISE 23 
III. BRYOPHYTES 


1. Hepaticar (Liverworts) 

The great division of plants known as Bryophytes comprises 
the liverworts (Hepaticae) and the mosses (Musci). The char- 
acteristics of this group, as contrasted with the Thallophytes, are: 
(1) The establishment of a definite alternation of generations. 
Distinct sexual and sexless individuals alternately produce each 
other, the gametophyte producing the sex organs (containing 
gametes), the sporophyte producing asexual spores. The differ- 
ence between the alternation of generations here and in the 
algae is that one (the sporophyte) is more or less dependent upon 
the gametophyte. (2) The appearance of the archegoniwm. 
This is the organ which produces the egg (female gamete). The 
archegonium is a flask-shaped organ consisting of a jacket of 
sterile cells. (3) The appearance of a multicellular antheridium. 
A multicellular antheridium was found among the algae in 
Ectocarpus and Chara, but this one is uniform throughout the 
Bryophytes and has a characteristic structure. 

The liverworts are thallose plants found growing in moist 
situations along streams and lakes or in moist shady places in 
the woods. The gametophyte is the larger and more conspicuous 
generation. A characteristic feature of this plant is its dichoto- 
mous method of branching. They may be monoecious or dioe- 
cious, but, in either case, the sex organs are, as a rule, produced 
on the upper surface in depressions, grooves, or special eleva- 
tions. When the egg is fertilized, it begins to grow into the 
sporophyte plant, which, in the liverworts, remains in the tissues 
of the mother plant and is more or less parasitic on it. 

Riccia. This is the simplest of liverworts. Study the plant 
with the naked eye and with a magnifying glass. Make an ac- 
curate sketch of two kinds; the shorter, heavier one is more con- 
fined to ground or mud, the longer, narrower one to a floating 
habitat. From a prepared slide of longitudinal sections of this 
plant, search for archegonia. Notice the flask-like shape. Where 
is the egg located? How is fertilization brought about? When 
the egg is fertilized it begins a series of divisions. Look for 
divisions of the fertilized egg. This is the young sporophyte. 


[ 60 ] 


BRYOPHYTES 


Look for stages where the cells are beginning to prepare them- 
selves for production of spores. These cells are called spore- 
mother cells. Each cell gives rise to four spores. This group 
of cells is called a tetrad, and each spore is called a tetraspore. 
Draw a tetrad and a tetraspore. Draw also a mature sporo- 
phyte. What becomes of the archegonium? The sporophyte in 
this plant is, therefore, nothing more than a sporangium, the 
simplest sporophyte you can imagine. 

Although this plant is monoecious, you seldom find both male 
and female organs in the same plant. The reason is, that the 
antheridia are usually produced first. From prepared slides of 
younger plants look for antheridia. Make a drawing of a ma- 
ture antheridium. Notice the sterile jacket of cells on the out- 
side and the many-celled structure of it as a whole. Each cell 
on the inside produces a motile sperm. 


REFERENCES 


Campbell, D. H., Mosses and Ferns; Grout, A. J., Mosses 
With a Hand Lens; Evans, A. W. and Nichols, G. E., Bryophytes 
of Connecticut. 


[ 61 ] 


EXERCISE 24 
III. BRYOPHYTES 


1. Heparticar (Continued) 

Marchantia. This plant is a more advanced type than 
Riccia. What does that mean? In studying this plant, recall 
Riccia, and see how this differs from it. Study the plant as in 
the previous period. You will receive two plants. Why? Make 
careful sketches of the two plants. The stalk-like structures on 
the plants are the receptacles of the sex organs. How do they 
differ? Look for the rhizoids on the under side. This is called 
the ventral side ; the upper side is the dorsal. Also make a habit 
sketch of the plant showing cupules on the dorsal side. With a 
pin or needle, remove some of the green bodies found in the eup, 
put on a slide, and examine with low power. Make a drawing of 
one. These are asexual reproductive bodies. They are called 
gemmae. Has this plant any other asexual method of repro- 
duction ? 

The archegonia are located on the under side of the female 
receptacle, hence they are inverted. From prepared slides of 
sections of the receptacle, make drawings of archegonia showing 
the eggs. Draw a young and an old archegonium. From other 
prepared sections of the male receptacle, draw an antheridium. 
On which side of the receptacle are they located? This plant is 
said to be dioecious. What does this mean? Since the two sex 
cells, the egg and the sperm, are located in different plants more 
or less distantly separated, how is fertilization brought about? 
Does this have any relation to the plant’s habitat ? 

After fertilization has taken place what happens? From 
prepared slides of female receptacles, study the development of 
the fertilized egg. What does the egg develop into? Make a draw- 
ing of a young sporophyte. Also make a drawing of a mature 
sporophyte. How does this sporophyte differ from the one in 
Riccia? What is the part in which the spores are found called? 
The part which attaches it to the plant is called the foot, and 
the tissue between these two extremes is called the seta. Under 
high power, study the spores. Is there anything besides the 
spores in the sporangium. The string-like bodies mixed with 
the spores are called elaters. What is their function? What is 


[ 62 ] 


BRYOPHYTES 


the function of the foot and seta? Compare this sporophyte 
with that of Riccia. What is the main difference between them? 
This morphological difference is associated with nourishment and 
spore dispersal. 

Anthoceras. Make habit sketches of this plant. Notice that 
some plants have a projection on the dorsal side, while in some 
it is absent or very short. This is the sporophyte. What im- 
portant difference do you observe in this sporophyte and in the 
others studied so far? Obtain from the instructor a small piece 
of a mature sporophyte. Mash on a slide and examine. Draw 
aspore. From prepared slides of longitudinal and cross sections 
of the sporophyte make a sketch showing structures of the sporo- 
phyte. This is considered one of the most advanced types of 
liverworts. Explain. 

REFERENCES 

Grout, Mosses with a Hand Lens; Evans and Nichols, Bryo- 

phytes of Connecticut. 


[ 63 ] 


EXERCISE 25 
III. BRYOPHYTES 


2. Mosses (Muscr) 
Mosses are closely related to some of the higher (leafy) liver- 
worts. The characteristic differences between the two will be 
noticed in studying them. 


Sphagnum. This is known as bog or peat moss. It grows 
almost everywhere where the soil is saturated with water and 
especially where the soil is sour (acid). This does not mean 
that it does not grow also in other moist situations. The plant 
which you are studying is the gametophyte. What is peculiar 
about this gametophyte as compared with that of the liverworts 
studied? Make a habit sketch of one. What is the black knob 
at the tip? With a pin, remove a ‘‘leaf’’, place under micro- 
scope, examine, and draw. Notice that it is made up of two 
kinds of cells, some large with openings in them and others very 
long and narrow. The former are dead (hyaline) cells, while the 
latter are living and contain chlorophyll. What effect does this 
have upon the color of this plant? This plant has antiseptic 
properties and is a good absorbent. Why? The stalk which 
holds the sporophyte is called the pseudopodium (false foot). 
Why? Under a magnifying glass, draw a complete sporophyte 
with the lid on and one with the lid off. 

True Moss (Bryales). In studying true moss, determine just 
how it differs from the liverworts and Sphagnum. Most mosses 
are dioecious. The sex organs are located at the tip of the plant 
inside of a crown of leaves often called the moss ‘‘flower’’. 
Make sketches of male and female plants. How does this game- 
tophyte differ from the gametophyte of some of the Thallo- 
phytes? What are some of the organs present in this plant? 
What is the function of each of these organs? Your drawings 
should show ‘‘leaves’’, ‘‘stem’’, and rhizoids. In some mosses 
asexual bodies occur. Look for them. 

With a needle, remove the extreme tip of the male plant on to 
a slide, cover with water and a coverglass, and mash without 
breaking the coverglass. Examine. You should find antheridia. 
Draw one. Now do the same with the female plant. What 
should you find in this one? Draw an archegonium. If material 


[ 64 ] 


BRYOPHYTES 


18 available, draw also a young sporophyte. Determine what 
becomes of the old archegonium after the egg begins to grow. 

Study a moss plant with the sporophyte. Which gametophyte 
plant does it grow on? Why? Make a careful drawing of the 
whole plant. Pull out the sporophyte and study it with a magni- 
fying glass. Try to name the different parts. The paper-like 
funnel which is attached on the capsule is called the calyptra. 
What has it come from? Draw the capsule with the calyptra 
removed. With a needle, remove the lid, the operculum. Draw 
it and the capsule with operculum removed. With a lens, ex- 
amine the tip of the capsule (sporangium). Make a drawing of 
what you see. This is called the peristome. Its function is to 
remove the spores. Crush a capsule and draw the spores. 

When a spore germinates it does not produce the leafy game- 
tophyte directly ; it produces an alga-like growth. This is called 
the protonema (the first thread). Examine some of these and 
draw. 

REFERENCES 

Grout, Mosses With a Hand Lens; Grout, A. J., Mosses With 

a Hand Lens and Microscope. 


[ 65 J 


EXERCISE 26 
IV. PTERIDOPHYTES .- 
1. FERNS 

Pteridophytes are the fern plants. The outstanding charac- 
teristic of these plants is the presence of a highly developed and 
complex sporophyte and a reduced and simplified gametophyte. 
In Bryophytes the gametophyte is the outstanding generation ; 
in the Pteriodophytes the sporophyte is the outstanding gener- 
ation. In Bryophytes the sporophyte is more or less dependent 
on the gametophyte; in Pteridophytes the sporophyte has an 
independent existence. 

Filicales. These are the true ferns. Study a complete fern 
plant. Bear in mind that you are studying the sporophyte. 
Notice, this plant has leaves, stem, and true roots. What is the 
function of each? Make a sketch of a leaf. The green or brown 
patches (‘‘fruit dots’’) on the under side of the leaf are called 
sori. Draw some under a magnifying glass. With a needle, re- 
move the green cover, the indusium. With a needle, remove some 
of the sporangia on to a slide, add water and a coverglass, and 
study. Make a careful drawing of a sporangium. Then mash 
and draw the spores. The thick-walled, U-shaped cells on the 
edge form the annulus. What is its function? How are the 
spores shed ? 

A leaf producing spores is a sporophyll. Study and draw a 
plant in which all leaves are not sporophylls. Some leaves are 
specialized to bear spores, while others are only vegetative. 


When a spore germinates, what does it produce if the plant 
has alternation of generations? Examine a gametophyte with a 
magnifying glass and draw both dorsal and ventral sides. This 
plant is monoecious, and the sex organs are located on the ventral 
side. Can you see them with a magnifying glass? What plant 
does this gametophyte resemble? Next draw a gametophyte 
with the young sporophyte attached. How did this arise? 


From prepared slides, make drawings of archegonia and an- 
theridia. From other prepared slides, make diagrammatic draw- 
ings of cross sections of stems and roots of ferns. The outer- 
most tissue is the cortez. The thick-walled cells make up the 
xylem. The tissue inside the xylem, if any, is the pith. The 


[ 66 ] 


PTERIDOPHYTES 


xylem and the phloem together are called the stele. There are 
three principal types: the protostele, such as the one in the root; 
the siphonostele, such as the one in Adiantum; and the polystele, 
such as the one in brake fern (Pteris). 


REFERENCES 


Clute, W. N., The Fern Allies of North America; Waters, C. 
E., Ferns; Underwood, L. M., Our Native Ferns. 


[ 67] 


EXERCISE 27 
IV. PTERIDOPHYTES 


2. LycopopIALES 


These fern plants are commonly ealled club mosses because 
of the moss-like stem and their club-shaped appearance due to 
the large terminal strobili which some have. Besides the above 
characteristics, which are not found in ferns, they differ from 
ferns mainly in that in most of them the spore-bearing leaves, 
the sporophylls, are crowded together at the summit of the stem. 
This collection of sporophylls makes up what is called the 
strobilus. 

Lycopodium. There are several species of Lycopodium. The 
one you will study is Lycopodium complanatum. Make a habit- 
sketch of the whole plant. Then, with a needle, remove carefully 
a sporophyll and put it on a slide in a drop of water. Study it 
with a magnifying glass. Make a drawing of the upper side 
(the adaxial side), of the under side (the abaxial side), and of 
the side view. Is the sporangium: single or double? On which 
side of the sporophyll is it? Then, mash it with a coverglass and 
draw spores. 

From prepared slides, make a diagrammatic drawing of a 
cross section of the stem. What kind of a stele has this plant? 
The gametophyte of Lycopodium is a tuberous subterranean 
structure. If available, study and sketch. 

Selaginella. This plant is common along ditches and ponds. 
Make a drawing of the whole plant showing stem, leaves, strobili, 
and roots. Where do the roots appear? One peculiarity of 
Selaginella is that the spores are different. In the ferns already 
studied, the spores look alike. This is called homospory, and all 
such ferns are said to be homosporous. Selagineila, on the other 
hand, having different spores, is heterosporous, and this situation 
is heterospory. The different spores may be seen in a longi- 
tudinal section of a strobilus. From a prepared slide of this, 
make a drawing showing the different spores in the same strobi- 
lus. The small spores are called microspores. They give rise to 
the male gametophyte and may, therefore, be called male spores. 
The sporangium which holds the microspores is the microsporan- 
gium, and the sporophyll which produces the microsporangium is 


[ 68 ] 


PTERIDOPHYTES 


the microsporophyll. The large spores are called megaspores. 
They produce the female gametophyte and are, therefore, female 
spores. What is the sporangium called which produces the large 
spores? The sporophyll? 

Remove a sporophyll which bears large spores, examine with 
lens, and draw. On which side are the sporangia on this plant? 
Break a sporangium with a needle and draw. Do the same with 
the microsporophyll. 

If available, draw sections of male and female gametophytes. 
Also draw a female gametophyte with the young sporophyte 
attached to it. 

REFERENCE 


Coulter, Barnes and Cowles, Textbook of Botany, I. 


[ 69 ] 


EXERCISE 28 


V. FIELD STUDY 


Plant Life in the Autumn. The purpose of field work is to 
familiarize the student with plants in their native habitat—to 
study the plants at home. The student should observe every 
plant he sees. He should notice the following things: what kind 
of a plant it is, where it grows, what stage it is in, ete. It is well 
to bring a magnifying glass, a note book, pencil, and some bottles 
and pipettes. Take notes of everything learned and write up the 
trip as soon as possible, while your memory is fresh. Be especi- 
ally careful about the organization of the paper. Seattered facts 
do not mean much. State the facts in some orderly fashion 
together with the conclusion you have reached. 


[70] 





PART TWO 


OUTLINE OF PART II 


I, THE CELL 


1. Crtu DIvIsIon 
2. CELL DIFFERENTIATION 


II. SPERMATOPHYTES (SEED PLANTS) 


ie 


GYMNOSPERMS 


a. Cycads. Zamia 
b. Conifers. Pune, etc. 


ANGIOSPERMS 
a. Seeds 
(1) Morphology 


b. 


C. 


(2) 


(a) External Characters 

(b) Internal Characters 

(ec) Foods Stored in seeds 

Germination 

(a) Conditions Under Which Seeds Germi- 
nate 

(b) Respiration in Seeds 

(c) Growth of Seedlings 


Roots 


(1) 
(2) 
(3) 


Kinds of Roots 
Structure of Roots 
Physiology of Roots 


Stems 


(1) 


Kinds of Stems 

(a) Dicotyledonous Stems 
a. External Characters 
b. Internal Characters 

(b) Monoecotyledonous Stem 
a. External Characters 
b. Internal Characters 

(ec) Modified Stems 


[72] 


(2) Physiology of Stems 
(a) Rise of Sap in Stems 
(b) Geotropism 
(ec) Phototropism 
(d) Effect of Light on Growth 


d. Buds 
(1) Loeation of Buds 
(2) Kind of Buds 
(3) Structure of Buds 


e. Leaves 
(1) Morphology of Leaves 
(2) Kinds of Leaves 
(3) Phyllotaxy 
(4) Physiology of Leaves 
(a) Transpiration 
(b) Photosynthesis 
f. Flowers, Flower Clusters, Fruits, Etc. 
(1) The Willow (Salix) 
(2) The Oak (Quercus) 
(3) Cinquefoil (Potentilla) 
(4) May Apple (Podophyllum) 
(5) Wood Sorrel (Oxalis) 
(6) Veteh (Vicia) 
(7) Iris (Blue Flag) 
(8) Daisy (Chrysanthemum ) 
(9) Dandelion (Taraxacum) 


g. Embryogeny (in Capsella) 
h. Fruts 
v. Seed dispersal 
3. CLASSIFICATION AND INDENTIFICATION 


Tif. FIELD STUDIES 


EXERCISE 1 
I. THE CELL 


Cell Division. Using prepared slides of longitudinal section 
of root tips of Tradescantia virginica (Spiderwort), or some 
other plant, make a study of cell division. This shows a meristi- 
matic region. Under high power, draw accurately at least eight 
consecutive stages in the division of the nucleus. 

In your notes, answer the following questions: What is a 
meristimatie region? What is the function of cell division? 
What are chromosomes? What is the function of chromosomes? 
What is the function of the nucleus? In what part of the root 
tip is cell division most abundant? What is the difference in 
appearance, size, and shape between the cells in this region 
and those which are not dividing? What is meant by ‘‘con- 
stancy of chromosomes’’? What is the distinction between 
mitosis and amitosis? 

Cell Differentiation. From prepared slides of the cross sec- 
tion of a stem, make accurate drawings of as many different 
cells as you can find. How do these cells differ from the cells 
studied in the root tip? How do they differ from each other? 
What is a group of similar cells called? Where does the thick 
wall come from? Do all these cells have protoplasts? If they 
do not, what kind of cells are they? 


REFERENCE 
Sharp, An Introduction to Cytology. 


[74] 





EXERCISE 2 
II. SPERMATOPHYTES 


1. GyMNOSPERMS 
a. Cycads 

Zamia. These are the simplest of the living seed plants. 
Make a habit sketch of Zamia pumila. Note the tuberous stem 
and compound leaves. All of them are tropical to subtropical. 
This plant grows in Florida. Note also the position of the 
strobilus (cone). Make a drawing of a female strobilus. From 
a broken cone, secure a megasporophyll and draw it. Where 
are the megasporangia? In some cones the megasporangium is 
small. What does this mean? Secure a seed and sketch it, show- 
ing the micropyle. With a sharp knife, split the seed open and 
study the contents. Draw, showing the different parts of the 
embryo and seed coats. Make a drawing of a section of a seed 
showing archegonia. Make a drawing of a male strobilus. How 
does this differ from the female strobilus? From a broken 
cone, secure a miscrosporophyll and draw side and lower views. 
What are the small spheres on the under side? Draw one, 
using a magnifying glass. Mash a microsporangium on a slide 
and examine under a microscope. Draw a few microspores. 

How do these plants differ from the ferns? How do they 
differ from Selaginella? What is the seed? What does the 
endosperm come from? From external and internal appear- 
ances the seeds look alike. Are they? Explain. Where is the 
female gametophyte? What structure in this plant is called 
pollen? What does this structure correspond to in Selaginella? 
What is the function of the pollen tube? The sperms in this 
plant have cilia; what does this signify? How is fertilization 
brought about in this plant? What is pollination? How does 
it take place in this plant? 


REFERENCES 


Chamberlain, C. J., The Inving Cycads; Coulter, Barnes, and 
Cowles, Textbook of Botany, I. 


[76] 


EXERCISE 3 
II. SPERMATOPHYTES 
1. GyYMNOSPERMS 
b. Conifers 

Pine (Pinus). This is the most widely distributed gymno- 
sperm. Make a habit sketch of a twig of pine showing leaves 
and the old female strobilus. How many leaves are there in each 
bunch? From prepared slides, make a careful drawing of a 
cross-section of a leaf. What does the shape and structure of 
this leaf signify as to climatie conditions to which this plant is 
adapted? Make a diagrammatic drawing of a cross-section of a 
young shoot. Explain how the stem increases in thickness. 

From what part of the stem does wood come? What is it 
called. What is its function? From prepared slides, make 
accurate drawings of cross, tangential, and radial sections, show- 
ing medullary rays, bordered pits, and rings of growth. Make a 
diagram of a stem showing how these sections were cut. From 
these three sections, reconstruct a tracheid showing form and 
position of bordered pits. What is the function of the bordered 
pits? Medullary rays? What are rings of growth? How do 
they appear in wood to the naked eye? What is the summer 
and autumn wood? Which is the spring wood? What differ- 
ence is there in the cells of each? What is the explanation for 
this difference? Discuss the economic uses of pines. Discuss 
their present and past distribution. 

Other gymnosperms are Red Cedar (Jumperus), Arbor Vitae 
(Thuja), Larch (Larix), Cypress (Taxodium), ete. Make habit 
sketches of as many of these as are available. 


REFERENCES 


Coulter, Barnes and Cowles, Textbook of Botany, 1; Coulter, 
J. M. and Chamberlain, C. J., Morphology of Gymnosperms. 


[ 78 ] 





EXERCISE 4 
II. SPERMATOPHYTES 


1. GYMNOSPERMS 
b. Conifers (Continued) 

Pine (Pinus) Reproduction. Make a sketch of a female 
strobilus. From a broken cone (strobilus), remove the bract- 
like structure and draw side and upper views. What is this 
structure? In what way does it differ from the corresponding 
structure in Syeads? From prepared slides, draw a section 
through a megasporangium showing gametophyte with arche- 
gonia. Draw a mature seed. How does this differ from the seed 
in Cycad? What is the function of the bract (wing)? Draw 
a young pine (seedling). Make a drawing of a male strobilus. 
How does it differ from the female? From a broken cone, 
(strobilus) secure a microsporophyll and draw side, end, and 
under side views. How does this differ from the microsporo- 
phyll of Cyecads? Mash a microsporangium on a slide and ex- 
amine under a microscope. Draw a few microspores (pollen 
grains). How do they differ from the pollen in Cyeads? From 
prepared slides, diagram the longitudinal section of a male 
strobilus. From cross sections of a mature male strobilus, make 
a careful drawing of a pollen grain under high power, showing 
cell walls and nucleus or nuclei. 

Are pines monoecious or dioecious? How is pollination 
brought about? What is meant by gymnosperms? Where does 
the microspore germinate? What is it called after it germinates? 
Does the male gametophyte of gymnosperms have an antheri- 
dium? How many sperms does it produce? The sperms in pine 
are non-motile. What does this signify? 


REFERENCES 


Coulter and Chamberlain, Morphology of Gymnosperms; 
Coulter, Barnes and Cowles, Textbook of Botany, I. 


[ 80 ] 





EXERCISE 5 
II. SPERMATOPHYTES 
2. ANGIOSPERMS 
a. Seeds 

Morphology of Seeds (External Characters). Examine the 
seeds and note their color, surface, and markings. Look for a 
sear (hilum), the place where it was attached to the inside of 
the fruit. Look for a small swelling (the chalaza). Look for 
the ridge (the raphe) which runs around some seeds. Look 
for a tiny opening (the micropyle). Describe and draw the 
outside view of each seed studied and name all parts shown. Note 
caruncle on the eastor bean. What is its function? Draw a 
seed of cotton and milkweed. What is the function of the lint 
for the plant? 

Examine seeds soaked and dry. What is the effect of soak- 
ing seeds? How does the water enter the seed? What is the 
result ? 

Internal Structure. Dissect the different seeds and note the 
following structures: seed coat (testa), endosperm, embryo. Make 
drawings of inside views of the seeds showing the different parts. 
Classify seeds as to internal structure. What is the embryo? 
How does the embryo of the bean differ from the embryo of 
corn and of the castor bean? What are, cotyledons, radicle, 
plumule? 

Foods in Seeds. Scrape off a little from the inside of a seed 
on to a slide. Put on this a drop of iodine. Examine under the 
microscope. The blue particles are starch. Make drawings of 
starch from corn, bean, and pea under high power. Put iodine 
on the inside of other seeds. Which have starch? In what part 
of the seed is it? What seeds have no starch? In what forms 
is food stored in seed? Why are seeds of economic value? What 
are seeds used for besides food? What is the function of stored 
food in seeds? 

REFERENCES 

Coulter, Barnes and Cowles, Textbook of Botany, I1; Ganong, 
W.F., A Textbook of Botany; Martin, J. N., Botany with Agri- 
cultural Applications; Weatherwax, P., The Story of the Maize 
Plant. 


[ 82 ] 





EXERCISE 6 
II. SPERMATOPHYTES 


2. ANGIOSPERMS 
a. Seeds (Continued) 

Seed Germination. Examine the four bottles labeled Ai, B1, 
C1, and D1. Make sketches of them showing the condition of 
the seeds. In which bottle have the seeds germinated best? 
Why have not the seeds germinated in the other bottles? Explain. 

Examine the three bottles labeled A2, B2, C2. A2 has been 
kept outside; B2, on a radiator; C2, in a warm room. Which 
has germinated best? Explain. Make drawings of the bottles, 
showing the condition of the seeds. 

Glue a piece of cotton on the bottom of a tumbler. Put 
a few soaked seeds in a small dish placed in a Petri dish filled 
with water. Light a match and ignite the cotton in the tumbler 
and quickly invert it over the seeds. What happens? Explain. 
Examine at the following period. Make drawings of the two 
tumblers, indicating differences, and explain fully. 

Secure some lime water or barium hydroxide. Put some in 
a glass and blow into it with a glass tube. What happens? 
Explain. Germinate some oats in a closed bottle with a tube 
passing through the cork. After a day or two, pass the gas 
above the seeds into lime water by filling the bottle with water 
through a funnel. What happens? Explain. Draw the appa- 
ratus. Draw a respiroscope and explain its use. 

Examine germinatng seeds of squash. What part of the 
embryo comes out of the seed coat first? Note the root hairs. 
Do the cotyledons in the squash turn green? Draw several stages 
in the germination of the squash. 

Study germinating seeds of pea, bean, corn, and oats. How 
does the germination of the pea differ from the germination of 
the squash? How do the germination of corn and oats resemble 
each other? How do they differ from germinating seeds of other 
plants studied? What is meant by hypogeal and epigeal germi- 
nation? Draw several stages in the germination of corn, pea, 


bean, and oats. 
, REFERENCES 


Coulter, Barnes and Cowles, Textbook of Botany, I1; Ganong, 
Textbook of Botany; Martin, Botany with Agricultural Applica- 


tions. 
[ 84 ] 





EXERCISE 7 
II. SPERMATOPHYTES 


2. ANGIOSPERMS 
b. Roots 


Kinds of Roots. Make a study of a root of clover. The root 
coming directly below the stem is the primary root. Note that 
the root has branches. These are lateral roots. Note the tuber- 
cles. From prepared slides, make a diagrammatic drawing of 
sections of tubercle and root. Under high power, draw a few 
cells from the tubercle, showing bacteria. What relationship is 
shown here? Of what biological significance are these bacteria? 
What effect do they have upon the soil? What would happen 
to plants if such organisms did not exist? 

Make a study of the root of dandelion. How does it differ 
from the root of clover? The main root is called the tap root. 
Also make a study of turnip or parsnip root. This tap root 
is known as a fleshy root. Place some scrapings from the inside 
of the root on a slide in a drop of iodine. Does it contain starch? 
What is the function of the fleshy root? What relation is there 
between these plants and the flowering period? Fleshy roots of 
dahlia are called fascicled roots. Make a list of roots used as 
foods? 

Study the stem of ivy and wandering jew. Roots occurring 
in unusual places are called adventitious roots. If they grow 
on aerial parts they are called aerial. What is the function 
of aerial roots in ivy? In wandering jew? In strawberry? Do 
they appear in any special part of the stem? Why? 

Study roots of corn, wheat, or any grass plant. These are 
ealled fibrous roots. 

Structure of Roots. From prepared slides of a longitudinal 
section of a root tip, make a diagram showing the root cap. What 
is its function? From prepared slides, make a diagrammatic 
drawing of a cross section of a root. Does the root have bark? 
Does it have wood (xylem) ? 

Physiology of Roots. What is the function of roots? Explain 
fully. Study demonstration experiments to show how roots ab- 
sorb water (osmosis). Explain. Draw apparatus. How do 
roots absorb inorganic salts. Study the experiment showing 


[ 86 ] 


SPERMATOPHYTES 


roots forcing water up the stem (root pressure). Explain. Study 
the experiment showing the effect of gravity on root. What is a 
tropism? Is this positive or negative, and what is this tropism 
called ? 
REFERENCES 

Coulter, Barnes and Cowles, Textbook of Botany, I1; Ganong, 
A Textbook of Botany; Martin, Botany with Agricultural Appli- 
cations. 


[ 87 ] 


EXERCISE 8 
II. SPERMATOPHYTES 


2. ANGIOSPERMS 
c. Stems 

Dicotyledonous Stem. Examine the stems of alder and cherry. 
These are woody stems. Stems with little wood (e.g. Coleus) 
are called herbaceous stems. Do the branches appear singly or 
in groups? Where are the leaf scars? What relation do the 
buds have to the leaf scars? The portion of the stem where a 
branch or leaf scar is found is called a node. The portion be- 
tween the leaf scars is called an internode. The branching of 
alder is called alternate or spiral. Lood for bud scars. From 
these scars can you tell the age of a branch? Do you find any 
other markings on the bark? Make sketches showing method 
of branching, position of buds, leaf sears, bud sears, and lenticels. 

Examine a stem of maple, ash, or lilac. Compare this with 
the stems above. What is the difference in branching? Note 
other differences. Are the buds of any one pair directly above 
those of the next lower pair? This branching is called opposite. 
Make a sketch showing the characters mentioned above. 

Diagram the cross section of a young stem of basswood. 
Label the different parts. Also diagram a section of Ampelopsis 
(ivy) stem. Make a careful and accurate drawing of a sector 
of the section of Ampelopsis including a vascular bundle. 

Monocotyledonous Stem. Make a careful study of the stem 
of corn, bamboo, or wandering jew. How do they differ from the 
stems studied above? Note the definite nodes and internodes. 
Do these stems have bark? Do they branch? If so, how? 
Make a sketch showing all external characters. 

From prepared slides, diagram a cross section of a stem of 
Asparagus. Also make an accurate drawing of a section of a 
stem, including a vascular bundle. How does the internal struc- 
ture of the stem of monocotyledons differ from that of dicotyle- 
dons? 

Modified Stems. Examine a flat-stemmed (Muehlenbeckit) 
plant. How does this stem differ from other stems studied? 
How does it resemble a leaf? 


[ 88 ] 


SPERMATOPHYTES 


Examine the underground stem of Solomon’s Seal. Why 
is this called a stem? Where are the nodes and internodes? 
One internode is produced each year. The attached leaf is the 
winter leaf. Look for the bud. Where are the roots attached? 
What is the function of the underground stem? Test it for 
starch. 

Study a potato. This is called a tuber. It is an underground 
stem. What are the ‘‘eyes’’? Draw a potato not sprouted and 
one which is sprouting. Test the potato for starch. Draw a few 
starch grains. 

Study corms of gladiolus. This is also an underground stem. 
Make a sketch of a whole stem and of one which is split. In 
your notes enumerate the functions of stems and their economic 
uses. 

REFERENCES 

Ganong, A Textbook of Botany; Strassburger, Textbook of 
Botany (5th Ed.); Coulter, Barnes and Cowles, Textbook of 
Botany, I1; Martin, Botany with Agricultural Applications ; 
Coulter, J. M. and Chamberlain, C. J., Morphology of Angios- 
perms. 


[ 89 ] 


EXERCISE 9 
II. SPERMATOPHYTES 
2. ANGIOSPERMS 
c. Stems (Continued ) 

Physiology of Stems. Cut off a piece of geranium stem 
about three inches long. This is a dicot stem. Cut off the leaves 
near the stem. Place the lower end in a solution of eosin. 
After an hour, examine. Does the red solution rise in the stem ? 
What makes it rise? Make a thin section of the stem with a seal- 
pel. Mount on a slide and examine with a lens. In what part 
of the stem does the eosin rise? Make a diagram of the stem 
section showing where the solution rises. 

Cut off a piece of wandering jew and place it in eosin solu- 
tion. This is a monocot stem. Proceed as above and make the 
same observations. Make a section, examine with lens, and 
diagram as above. Note differences between a dicot and a 
monocot stem. 

Mash a piece of an herbaceous stem on a slide; add water and 
coverslip. Examine the tubes (tracheae). How do these tubes 
differ from the tracheids in pine? Make drawings of spiral and 
pitted ducts. 

Make a sketch of a young plant placed horizontally. After a 
few days, examine and draw again. What has happened? What 
relation is shown in this experiment? What is this phenomenon 
called? Compare this with a similar root experiment. What 
kind of a tropism is shown here? Is it positive or negative? 

Make a sketch of a plant placed in such a way that it is 
illuminated from one side only. Examine after a few days. 
What has happened? What relation is shown in this experi- 
ment? What is this phenomenon called? 

Place a young corn plant in a perfectly dark room. Leave 
for several days. Examine and note results. What effect does 
light have on development of chlorophyll? What direct effect 
does light have on growth? 


REFERENCES 


Ganong, A Textbook of Botany; Coulter, Barnes and Cowles, 
Textbook of Botany, I1; Dixon, H. D., Transpiration and the 
Ascent of Sap in Plants. 


[ 90] 





EXERCISE 10 
Il. SPERMATOPHYTES 


2. ANGIOSPERMS 
d. Buds 

Examine twigs of various woody plants, such as ash, alder, 
maple, beech, and sweet gum. Note the position of the buds 
in the axils of the leaves. Define axil. If the stem has no 
leaves, their position will be indicated by leaf sears. Note the 
size, shape, color, character of surface, and the number of 
buds at a node on the different plants. Do you find more than 
one bud in any one axil? If there are more than one, the others 
are called accessory buds. Do you find buds in other places 
than in the axil of the leaf? Such buds are called adventitious 
buds. Do you find a bud at the top of the branch? Such a bud 
is called a terminal bud. Buds which appear in axils of leaves 
are called lateral buds. Classify buds according to position. 

Sketch buds of the different types, being careful to show the 
external characteristics of each one. 

With forceps, carefully loosen the bud seales of the lateral 
buds of the sweet gum. Arrange these buds in a row on a 
sheet of paper and sketch. Compare the inner and outer surface 
of the scales. What do you find inside the scales? Make a 
sketch of the bud after the scales are removed. The arrangement 
of the leaves in the bud is called vernation. Note the arrange- 
ment. Pull off the young leaves, place them on paper, and 
sketch. 

Remove the scales from one of the larger terminal buds. 
What do you find in this type of bud? Classify buds by contents. 

Make a median longitudinal section through a bud on a twig 
with a sharp scalpel. Examine the outside and sketch. Is the 
bud continuous with the stem? Why? 

What is the function of buds? Supposing that at some time 
in the past plants had no buds, explain how they may have 
arisen. 

REFERENCES 

Martin, Botany with Agricultural Applications; Smith, G. 
M.; Overton, J. B.; Gilbert, E. M.; Denniston, R. H.; Bryan, G. 
S. and Allen, C. E., A Textbook of General Botany. 


[92] 


‘1-0 oe 2 i eo ee 





7 


Diao 


EXERCISE 11 


Il. SPERMATOPHYTES 
2. ANGIOSPERMS 
e. Leaves 

Morphology of Leaves. Study leaves of geranium (Perlar- 
gonium). Note the shape of the blade and the arrangement 
of veins. This vein type is called palmate. Is the edge smooth 
or uneven? Is the epidermis smooth or hairy? What is the 
petiole? Does it have stipules? Draw the entire leaf, showing 
the three main parts of a leaf, veins, and the character of the 
edge of the leaf. This is a dicot leaf. 

Carefully remove a piece of the epidermis, mount on a 
slide, and study under the microscope. Do all the cells in the 
epidermis have chlorophyll? What cells have? Why? Draw 
a piece of the epidermis showing the shape of cells and stomata. 
Also draw an epidermal hair. What is the function of these 
hairs in geranium ? 

Carefully remove a piece of the epidermis from the under 
side of the leaf. Mount and study as above. Also draw a piece 
showing the things seen above. Do you notice any differences? 
If so, what are they? 

Study a leaf of wandering jew. Note the vein arrangement, 
shape of blade, and edge. This is a typical monocot leaf. Is 
it a complete leaf? What part or parts are missing? Draw care- 
fully, showing all the characters noted above. How does it 
differ from the geranium leaf? 

Carefully remove a piece of the epidermis on the upper side. 
Mount, study, and draw as above. Note the differences from 
geranium leaf epidermis. 

Remove a piece of the lower epidermis. Mount, study, and 
draw as above. How does this epidermis differ from the upper? 
From what you have seen, enumerate differences between the two 
leaves studied. 

From prepared slides, study a cross section of some typical 
leaf. Draw accurately a cross section showing the following 
structures: upper and lower epidermis, stomata, air chambers, 
mesophyll, and palisade cells. 


[ 94] 


SPERMATOPHYTES 


In your notes, discuss and answer the following questions: 
Why is a leaf usually flat and thin? Why does not the epider- 
mis have chlorophyll? Why do guard cells have chlorophyll? 
What is the function of guard cells, and how do they work? 
What are air spaces for? What is the function of the palisade 
cells? How are they specialized to meet this function? Why 
are stomata usually found only on the lower side? 

Discuss fully the function of leaves. 


REFERENCES 


Ganong, A Textbook of Botany; Strassburger, Textbook of 
Botany (5th Ed.) ; Martin, Botany with Agricultural Applica- 
tions. 


[ 95 ] 


EXERCISE 12 
II. SPERMATOPHYTES 


2. ANGIOSPERMS 
e. Leaves (Continued) 

Compound Leaves. Examine leaves of clover, vetch, elder, 
Virginia creeper. These plants have compound leaves. Each 
small leaf is called a leaflet. Note the number and arrangement 
of leaflets. Compare with venation studied in simple leaves. 
Compound leaves are named in the same way; e.g. palmate, pin- 
nate, ete., compound. 


Modification of Leaf Structures. Examine leaves of vetch, 
smilax, barberry, and grape. Which are simple? Which com- 
pound? Look for the three parts of a leaf. What kind of stems 
are present in vetch, smilax, and grape? How are these stems 
held up? What structures are modified to hold the plant up 
in each case? What structures are modified into spines in 
barberry? Make drawings showing these modified leaves. 


Examine leaves of sundew, pitcher plant, and Venus Fly- 
trap. How are these modified? What function have these leaves 
assumed? In your notes explain how these leaves function? 
Also examine with a hand lens the water plant, Utricularia, and 
draw. 

Phyllotaxy. Study leaf arrangements of the following 
plants: Japanese honeysuckle, Galewm, ete. Note the number of 
leaves at each node. Two leaves at a node are called opposite ; 
more than two, whorled; one at a node, alternate. In alternate 
leaved plants, work out the leaf formulae. Select a leaf, then, 
beginning with the next leaf above, count the number of leaves, 
including the leaf directly above the one selected. Now deter- 
mine the number of times required to go around the stem. 
Use the number of the leaves as the denominator and the number 
of times required to go around the stem as the numerator. 
You now have a fraction which expresses the formula of leaf 
arrangement. This is called phyllotaxy. 

Study of Transpiration. Cut off a geranium leaf near the 
stem. Put the petiole through a hole in a piece of cardboard. 
Place the cardboard over a tumbler of water so that the petiole 
extends an inch or so in water. Cover the whole with another 


[ 96 ] 


SPERMATOPHYTES 


inverted tumbler. Leave for some time and observe. Where 
does the moisture on the sides of the inverted tumbler come 
from ? 

Place a branch with leaves of some woody plant in the poto- 
meter. Seal the space around the stem air tight. Adjust the 
colored water column in the graduated tube. Why does it move? 
Take the time and determine how many spaces it moves per 
unit of time in the darkened room. Try it in the window where 
there is a breeze but no sunlight. Does it move faster? Why? 
Try it in the sunlight. Does it move faster? Why? In your 
notes discuss fully transpiration. 


REFERENCES 


Ganong, A Textbook of Botany; Coulter, Barnes, and Cowles, 
Textbook of Botany, 11; Martin, Botany with Agricultural Ap- 
plication; Dixon, Transpiration and the Ascent of Sap in Plants. 


[ 97 ] 


EXERCISE 13 
Il. SPERMATOPHYTES 


2. ANGIOSPERMS 
e. Leaves (Continued ) 

Study of Photosynthesis. Place a potted geranium plant with 
large, healthy leaves in a perfectly dark room. Leave it for 
twelve hours. Place a light screen on it with spaces exposed. 
Place the plant in a window in a good light and leave for an 
hour. Remove a leaf from the plant before exposing it to the 
light, one after the plant has been exposed, and the one with 
the light sereen. Place these in hot water, then in alcohol until 
leaves are white. Wash in water. Then put in a weak iodine so- 
lution on a flat white dish. Which leaves turn blue? Do the 
leaves turn blue all over? Reeall your test for starch in seeds. 
Explain. 

Place a water plant (Elodea or Myriophyllum) under an 
inverted graduate filled with water. Place one in a dark room 
and another in light. Observe after several hours. Is the water 
replaced by gas in graduates? In which graduate is it replaced 
more? What is this gas? 

Collect a quantity of rich green leaves. Place them in alcohol 
and heat until the aleohol has turned a rich green. Pour off 
the liquid in a bottle. Examine in transmitted and reflected 
light. The appearance of a different color in reflected light from 
transmitted light is called fluorescence. This is one property 
of chlorophyll. What is the color in reflected light ? 

Examine the demonstration photosynthometer and _ sketch. 
Your instructor will explain how it is operated. Then solve 
this problem. Suppose you have added carbon dioxide to air 
till you have a ten per cent. mixture of carbon dioxide. What 
percentage of oxygen will you have? After leaving in light 
until all of the carbon dioxide has been used up, what percent- 
age of oxygen will you have at end of the experiment. 


REFERENCES 


Ganong, A Textbook of Botany; Coulter, Barnes and Cowles, 
Textbook of Botany, I1; Martin, Botany with Agricultural Ap. 
plications. 


[ 98 ] 





EXERCISE 14 
II. SPERMATOPHYTES 


2. ANGIOSPERMS 
f. Flowers 


Willow (Salix). Note that there are two kinds of bodies 
‘growing on the branches. Each of these bodies is composed of 
many flowers. These occur on different plants. This body is 
called a catkin or ament. Draw branches, showing the two kinds. 
of catkins. 


Examine a yellowish catkin. Note the yellowish organs com- 
posed of a stalk with an enlarged body at the end. The whole 
organ is a stamen. The stalk is the filament, and the knob is the 
anther. How many divisions in each anther? Note that a yel- 
lowish powder falls from the anthers. This is the pollen. How 
many stamens in a group? Notice the scale below each group. 
Is this seale smooth or hairy? Remove a seale with its stamens. 
These stamens with their scale constitute one kind of a flower in 
the willow. It is called a staminate flower. What is a stamen 
in terms of alternation of generations? A staminate flower? 
Draw a flower showing scale and stamens. Examine some pollen 
grains under high power. Are they smooth or rough? 


Examine the other kind of catkin. Note the scales. Note 
also the flask-shaped green body in each scale. It is called 
the pistil. The brownish part at the top of the pistil is called 
the stigma. How many divisions has it? The pistil with its 
scale is called the pistillate flower. Make a drawing of a pistil 
with its seale. The lower part of the pistil is called the ovary. 
Make a cross section of it. Examine with a lens and draw. 
The round bodies in it are ovules. These will develop into 
seeds when the eggs in them are fertilized. By what agent is 
pollination accomplished in the willow? 

Examine the stigma with a lens or microscope. Do you 
see any pollen grains on it? Draw a stigma showing the charac- 
ter of surface and pollen grains if you find any. The stalk 
on which the stigma is located is called the style. 


REFERENCE 
Densmore, H. D., General Botany. 


[ 100 ] 





EXERCISE 15 
II. SPERMATOPHYTES 


2. ANGIOSPERMS 
f. Flowers (Continued ) 

The Oak (Quercus). Examine carefully branches of white 
oak with the dangling bodies near the tips. These are called the 
inflorescences or aments. From what years growth do they 
arise? Do they arise from buds? How many aments arise 
from each bud? On this year’s growth, look for female flowers 
in axils of leaves. Make a sketch of a whole branch showing male 
and female flowers. The oak is moneocious. 


With a hand lens examine a male flower. Draw it, showing 
the number of stamens and any accessory parts. Compare with 
willow. Remove a stamen and draw, showing the number of 
divisions of the anther. 


With a hand lens examine a female flower. Draw it, showing 
the number of pistils and accessory parts. With a scalpel make 
a median longitudinal section through the pistil. Determine 
the number of ovules in each pistil. What kind of fruit does 
the oak produce? 


Examine branches of black oak. Do you find acorns on the 
last year’s branches? When do these mature? How does this 
oak differ in habit of reproduction from the white oak? Sketch 
a branch showing one-year old acorns, male flowers, and female 
flowers. 


Examine an acorn; sketch. What does the cupule come from ? 
The acorn? Break open an acorn and note contents. Does it 
have endosperm? Sketch the embryo showing cotyledons, plu- 
mule, and radicle. Why is the acorn a fruit instead of a seed? 

Make a field study of the oaks. Examine acorns and look 
for one germinating. Why do not more acorns germinate? If 
you find one germinating make a sketch of it. Learn the names 
of as many oaks as you ean find and their distinguishing echar- 
acteristics. 

REFERENCE 


Densmore, General Botany. 


[ 102 ] 





EXERCISE 16 
II. SPERMATOPHYTES 


2. ANGIOSPERMS 
f. Flowers (Continued ) 

Cinquefoil (Potentilla). Examine the plant. Note form and 
the relative size of the root, stem, leaves, and flowers. What 
kind of leaf has this plant? If a flower bud is present show 
that also. 

Make careful drawings of the flower from under and upper 
views. Split the flower longitudinally and draw it, indicating 
the relative position of the parts of the flower and the number. 
Determine the number of sepals, petals, pistils, and stamens. 
Note the arrangement and make a floral diagram of the flower 
according to diagrams on pages 326, 328 and 329 in Ganong’s 
Text Book of Botany. 

Remove a sepal and sketch. Is it smooth or hairy? What 
is this organ for? The sepals taken together make up the 
calyx. Examine a bud and determine the arrangement of sepals 
in the bud.. If they are arranged edge to edge they are valvate; 
if they are overlapping they are either convolute (spiral) or 
imbricated in more than one whorl. 

Remove a petal and sketch. What is this organ for? The 
petals taken together make up the corolla. The calyx and the 
corolla make up the perianth. Examine a bud; remove the calyx 
and sketch, showing the arrangement of petals. 


Remove a stamen and draw under a lens. How many divi- 
sions in the anther? Put some pollen on a slide and examine 
in transmitted and reflected hight. Draw a pollen grain under 
high power. From prepared slides draw accurately a cross 
section of an anther. 

Remove a pistil and draw under a lens. Is it simple or 
compound? Make a section through the ovary and sketch. How 
many ovules are there in each ovary? What kind of a fruit 
does this plant produce? 


REFERENCE 
Robbins, W. W., Botany of Crop Plants. 


[ 104] 





EXERCISE 17 
II. SPERMATOPHYTES 


2. ANGIOSPERMS 
f. Flowers (Continued ) 

May Apple or Mandrake (Podophyllum). Observe the habit 
of the plant. What kind of stem has it? What kind of leaf? 
Where do the roots arise? What kind of roots has it? Where 
is the flower located? Make a habit sketch of the plant showing 
stems, leaves, flowers, and fruit, if any. 

Study the flower. Make a habit sketch of it showing as many 
parts of it as possible. Determine the number of sepals, petals, 
stamens, and pistils. Remove sepals and petals and sketch 
one of each. Draw the flower with the perianth removed. Draw 
an individual stamen under a lens. Put some pollen on a dry 
slide, examine, and draw. Put some pollen in a drop of water, 
examine quickly, and draw. What is the difference? What 
is it due to? Draw a pistil. Make a longitudinal section of the 
ovary and sketch. Also make a cross-section and draw. Where 
are the ovules located? The place where the ovules are located 
is called the placenta. What kind of a fruit does this plant pro- 
duce? How is it pollinated? 

Make a diagram of the flower showing the number and posi- 
tion of flower parts including a section of ovary. 


Wood Sorrel (Oxalis). Examine flowers of this plant as 
above. Note especially whether the anthers are above or below 
the stigma. You should find both kinds of flowers. Such flowers 
are called dimorphic. What is the purpose of dimorphism ? 
Note that some flowers are yellow and some violet. This charac- 
teristic puts these plants into two species. Study this flower 
as in may apple. Note whether the ovary is simple or com- 
pound. Is the style single or divided? Note the relation be- 
tween the number of styles and the cells of the ovary. 

Draw the fruit. What kind of a fruit does this plant pro- 
duce? Select a plant with mature fruit. Touch a dry mature 
fruit. What happens to the seed? How is this phenomenon 
brought about? What is the purpose of it? 


[ 106 ] 


SPERMATOPHYTES 


The above flowers are perfect and complete. Why? From 
prepared slides make a drawing of a mature pollen grain 
under high power. How many nuclei do you find in each pollen 
grain? What are they? 

REFERENCE 

Densmore, General Botany. 


EXERCISE 18 


II. SPERMATOPHYTES 
2. ANGIOSPERMS 
f. Flowers (Continued ) 

Vetch (Vicia). Examine the flower of vetch. Note that it 
has an irregular flower. This is called a zygomorphic flower. 
What symmetry has it? Remove the petals carefully, arrange 
them as they are in the flower, and draw. The middle one is 
called the standard; the two on each side, the wings; and the 
one below, the keel. The keel is composed of two fused petals. 
What kind of calyx does this flower have? Draw the flower 
after the perianth has been removed. Show in your drawings 
the number of stamens. Are they all separate or united? Re- 
move stamens and draw the pistil. Is it simple or compound ? 
Draw a fruit. What kind of a fruit has it? Make a cross 
section of it and draw, showing the number of cells and where 
the ovules are attached (the placenta). How is pollination 
brought about in this plant? What kind of a flower has vetch? 
This flower is characteristic of the plant family called the 
Leguminosae. Name as many plants as you can which have this 
kind of fiower. 

Iris. Study the flower of wild iris (blue flag). This is an 
example of a flower in which the ovary is below the perianth 
(epigynous), and the perianth is partly united into a tube. 
Determine what are the sepals and petals. Where is the stigma? 
Is it single or divided? Where are the stamens? Draw the 
whole flower, showing the location of the ovary by dotted lines. 
Remove sepals and draw one. Draw a flower with the perianth 
removed. Draw a stamen. Examine tips of a stigma lobe. 
Note it is split with a lip on the under side. What is this lip 
for? Examine it with a lens. Do you see pollen grains on it? 
Explain fully how this plant is pollinated. Make a cross section 
of the ovary and draw under a lens. How many ‘‘cells’’ has it? 
How many ovules in each cell? Where are they attached? Is 
this a monocot or a dicot plant? 

Examine some pollen grains on a dry slide and draw. Are 
the grains small or large; smooth or rough? Drop some pollen 


[ 108 ] 


SPERMATOPHYTES 


grains in a ten per cent. sugar solution in a petri dish and leave 
over night. Examine next morning. What has happened? 
Sketch. 

REFERENCE 


Robbins, Botany of Crop Plants; Densmore, General Botany. 


[ 109 ] 


EXERCISE 19 

II. SPERMATOPHYTES 
2. ANGIOSPERMS 

f. Flowers (Continued ) 

The Daisy (Chrysanthemum). Make a sketch of the plant 
showing the flowers. Study the ‘‘flower’’. Note the green 
involucre. Is it made of more than one layer of bracts? This 
is a composite head with two kinds of flowers, the white ray 
flowers and the yellow disc flowers. Carefully remove a ray 
flower. Draw it. This is an epigynous flower. Does it have a 
calyx? How many petals are there? Are they all separate 
or united? Is it a perfect flower? Is it ‘‘fertile’’? About 
how many ray flowers are there? Do these flowers have bracts 
at the base? Study the dise flowers. What kind of a flower is 
this? Remove an open flower and draw under a lens. Does it 
have bracts and calyx? Remove the corolla. Are the stamens 
separate or united? Is this flower perfect? What kind of fruit 
does this plant have? 

The Dandelion (Tararacum). Make a sketch of this plant 
showing a flower cluster. How many kinds of flowers are found 
in each head? Remove a flower and sketch under a lens. What 
kind of a flower is this? Of how many petals is the corolla com- 
posed? Are the flowers perfect or imperfect? Where is the 
ovary located in relation to the corolla? Is there a calyx pres- 
ent? This is called pappus. Does each flower have a bract? 
How many stamens are there? Are they separate (distinet) or 
united? Examine the fruit. Sketch a fruit under a lens. 
What kind of a fruit is it? What is the circle of hairs at 
the top of the beak for? What part of the flower does it repre- 
sent ? 

These flowers are considered the most advanced. Compare 
these with the flowers studied previously, beginning with the 
willow. What is the difference between a primitive and an 
advanced flower? The composite head is considered the most 
advanced inflorescence. Compare this inflorescence with the 
flower clusters studied before. What are the characteristics of 
an advanced inflorescence ? 


REFERENCE 


Densmore, General Botany. 
[ 110 } 





[era 


EXERCISE 20 


II. SPERMATOPHYTES 
2. ANGIOSPERMS 
g. Embryogeny and seed development 

Shepherd’s Purse (Capsella). Make drawings of Capsella 
with flowers and fruit. Study the flower and note the kind of 
pistil it has. Draw a fruit separately. Carefully open a fruit. 
How many partitions (cells) has it? How many rows of 
ovules in each cell? Where are they attached? What kind 
of a fruit is it? This plant belongs to the Crucifer or Mustard 
family. Note how the fruit splits open. This kind of a fruit 
is called a silique. 

Study slides of sections of the young ovary of Capsella. These 
are serial sections cut longitudinally and parallel with the flat 
surfaces. Be sure you understand how the sections are cut 
and why they are cut this way. Examine a good section under 
low power and locate the ovules. Make a diagrammatic sketch 
of a good median section showing where the ovules are attached 
and divisions of the ovary. 

From these slides, make accurate drawings of the develop- 
ment of the embryo from the youngest to the most mature stages. 
In the younger stages you will have to use high power. What 
does this embryo come from? Do you see any endosperm? 
Study a drawing of a mature female gametophyte in Angios- 
perms. What does the endosperm come from in Angiosperms? 
In drawing the different stages of the embryo it is better to 
select first a rather advanced stage. Draw this, including the 
endosperm and the whole ovule. Then, look for younger stages. 
Only one stage will be found in one slide. Why? Do not draw 
the first one you see; search until a perfect embryo is found. 
It may not be in every section on a slide or on every slide. At 
least five stages should be drawn. 


REFERENCE 
Coulter, Barnes and Cowles, Textbook of Botany, I. 


[112] 





EXERCISE 21 


Il. SPERMATOPHYTES 
2, ANGIOSPERMS 
h. Fruits 

A fruit is a ripened ovary and its contents and, in some 
cases, accessory parts. Some fruits (achenes) like corn, wheat, 
oats, and other grains can hardly be distinguished from seeds. 
The fact that they are fruits can be shown from their structure 
and development. Fruits, from an economic standpoint, are 
ripened ovaries which are more or less fleshy and conspicuous. 
What is the function of such fruits? Young fruits are usually 
not palatable or edible. What advantage is this to the plant? 

Dry Indehiscent Fruits. You have already studied the grains, 
so these will be omitted in this exercise. Examine fruits of the 
following plants: maple, elm, basswood, Tree of Heaven, ash. 
What is peculiar about these fruits? What is the significance 
of this peculiarity? How do these fruits differ from achenes? 
What structure in the grasses peform the same function as the 
fruit appendages in the above? Draw these fruits. What are 
some of the other dry indehiscent fruits. How do they differ 
from the above? How is the function of seed distribution taken 
care of in these plants. What are these fruits called? 

Dry Dehiscent Fruits. Study fruits of Columbine, vetch, 
and mustard. How do these fruits differ from those studied 
above? Also study and sketch fruits of okra, poppy, and violet. 
What are these fruits called? How do they differ from those 
studied above ? 

Fleshy Fruits. Study the following fleshy fruits: plum, 
peach, grape, tomato, orange, and persimmon. Make drawings of 
whole fruit and of sections. How do the first two differ from 
the others? What are such fruits called? How many earpels 
make up each fruit? What is the ‘‘stone’’? How do the last 
three differ from the first two? What are they called? Study 
and draw cross and longitudinal sections of the apple and pear 
and explain the different regions. What is such a fruit called? 

Aggregate and Spurious Fruits. Make a thorough study of 
the following fruits: blackberry, strawberry, mulberry, pine- 
apple. Make drawings and explain what each part of the fruit 
stands for and how they are formed. 


{ 114 ] 


SPERMATOPHYTES 


REFERENCES 
Martin, Botany With Agriculture Applications; Ganong, A 
Textbook of Botany; Weatherwax, The Story of the Maize Plant. 


| 115 ] 


EXERCISE 22 
II. SPERMATOPHYTES 


2. ANGIOSPERMS 
i. Seed Dispersal 

Seed dispersal is just as important as seed production. In 
this exercise we are going to study the different methods that 
plants have of. distributing their seeds. It is not possible to 
study all plants in this vicinity which show peculiar adaptation 
for seed dispersal, because the fruits are not available at this 
season. You have already learned something about seed dis- 
persal in connection with the study of seeds and fruits. In the 
study of this subject, there are two principal things to bear in 
mind; namely, the nature of specialization and the specific agent 
involved? In this connection it is also well to recall the methods 
and agents for pollination. Why do you, in so many eases, see 
resemblances between the two processes ? 

Study the following fruits and seeds and make drawings of 
each type: cotton, milkweed, thistle, Clematis, beggars lice, Des- 
modium, Bidens, cockle burr, burdock, Paulownia, Devil’s 
needle, mullen, sand burr. Specify whether it is a seed or a 
fruit you are dealing with, what kind of fruit, and the agent 
or agents involved in each ease. 

Also make a study of the following: Oxalis (wood sorrel), 
stork’s bill, bitter cress (Cardamine), touch-me-not, squirting 
cucumber (the last two may be omitted if material is not avail- 
able), and geranium. 

In your notes, include a classification of the different methods 
of seed dispersal and eite examples in each elass. Also include 
a discussion of other plants not mentioned above and the econo- 
mic importance of this specialization. 


REFERENCES 


Martin, Botany With Agricultural Applications; Bower, F. 
O., The Living Plant; Strassburger, Textbook of Botany (5th 
Ed.) ; Coulter, Barnes and Cowles, Textbook of Botany, II. 


[ 116 ] 





EXERCISE 23 
Il. SPERMATOPHYTES 
3. CLASSIFICATION AND IDENTIFICATION 

Obtain several flowering plants from your instructor and a 
copy of Gray’s Manual. Study the plant carefully and deter- 
mine the following points: presence or absence of parts of 
flower, parts distinct or united, number of parts, relation of 
stamens to petals, kind of pistil, kind of ovary (simple or com- 
pound, number of compartments, or ‘‘cells’’). To determine the 
last, it is necessary to make a thin cross section of the ovary. 

Next, open the manual at the front and look for the place 
where it says ‘‘Spermatophytes’’. If your plant is a flowering 
plant it belongs of course to the ‘‘Angiosperms’’. Then, deter- 
mine whether it is a monocotyledon or dicotyledon. This may 
be determined from the number of sepals and petals and the 
veinings of the leaves. From here on the key is self explanatory. 
Should you find any term which you do not understand, look 
it up in the glossary in the back part of the book. 

What is Taxonomy? What relation does it have to identifi- 
cation? Where does this subject stand in the history of botany? 
Why? Why is it necessary to have it to-day? What is the 
‘*Binomial Nomenclature’’? How is it usually written? What 
are the advantages of a ‘‘scientifie name’’? What are the ad- 
vantages of a ‘‘common name’’? 

After each category below write the name of the division 
to which each plant you have identified belongs: 


Kingdom 
Division 
Class 
Order 
Family 
Tribe 
Genus 
Species 
REFERENCES 


Gray, A., Manual of Botany; Small, J. K., Flora of South- 
eastern United States. 


f 118 ] 





EXERCISE 24 
Wi FIEPLD: STUDY 


Plants in the Early Spring. Start with the same mental at- 
titude that you should have started out with in the autumn and 
with the same equipment. Notice how the plants differ from 
those in the autumn. Which plants have leaves on them, which 
have none? What plants are flowering? What plants are 
flowering before the leaves come out? How could you identify 
a plant in this season? What fruits do you find? What herbs? 
How have these herbs survived the winter? What is a rosette 
plant? Which did you find? Where do plants begin to grow 
first in the spring? What kind of plants are vernal flowers? 
What advantage is there in flowering early ? 

Study also the relation of plants to habitat. Which plants 
grow on uplands? Which grow on lowlands? Which in and 
near the water? 


Write a paper on this field trip. Include answers to the 
above questions, and add anything else you have learned by your 
observation. 


[ 120 ] 





EXERCISE 25 
II. FIELD STUDY 


Plants in the Late Spring. Bear in mind what you have seen 
on previous trips and compare it with what you see on this 
one. For example, what trees, shrubs, ete., blossom in the spring 
with the coming of the leaves? Which blossom after? Study 
the plants from the standpoint of -whether they are annuals, 
biennials, or perennials. Learn the names of all plants you 
see. Study the flowers vou find and classify them. How many 
weeds do you find? To what family of plants do most of them 
belong? Are they native (indigenous) or foreign (exotic). 
What is a weed? What plants are in fruit at this season? What 
are winter annuals? Name one or two. If possible study insect 
pollination. Write a well organized paper on what you have ob- 
served and the value of field work. 





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Date Due 


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Library Bureau Cat, no, 





980.2 Bé655Le 


177174 
Blomouist 







A Leborstory Manual of 
| Smee ie 177174 
580.2 B6o55L 


Biology Dent. Library 





